Crayfish.] 



MUSEUM OF ANIMATED NATURE. 



319 



seas of the Antilles. It is of a yellowish colour 

 mingled with red. 



From the geims Scyllarus is separated a form 

 termed Thenus, distinguished by the depression of 

 the body, which is narrowed from before back- 

 wards. The ocular peduncles are long, and the 

 eyes appear at each outer anterior angle of the 

 carapace. 



We select as an example the Thenus orientalis 

 (Fig. 3218), a native of the Indian Seas : it is about 

 eigiit inches in length. 



More singular still is the genus Ibacus, in which 

 the carapace is extremely wide, with a lamellar 

 expansion on each side covering the greater portion 

 of the feet, as in Calappa, among the crabs. These 

 expansions advance forwards, and are divided on 

 each side by a deep fissure, into two unequal por- 

 tions; the orbits are closer together than in Scyl- 

 larus or Thenus. The external lamelliform antennae 

 are of great expanse. Fig. 3219 represents in 

 outline the carapace of Ibiicus seen from above. 

 The Ibacus Peronii (Fig. 3220) is a native of the 

 Australasian Seas. It measures five inches in 

 length. 



In these three genera the first four pairs of limbs 

 terminate in a simple point, and in the males the 

 fil'th pair end similarly, but in the female terminate in 

 an incomplete pincer. There are four pairs of false 

 or abdominal feet ; in the female they are well de- 

 veloped. We now advance to a tribe of Macrura, 

 represented by the genus Palinurus, and termed 

 Langoustians by M. Milne Edwards, and charac- 

 terized by the absence of claw-pincers. 



The Palinuri or Langoustes have, says Cuvier, the 

 lateral antennae large, setaceous, and covered with 

 spines. "Among these Crustacea, called by the 

 Greeks KapaSas, and the Latins Locusta, respecting 

 which .■Aristotle has given many important observa- 

 tions, there are some which with age acquire the 

 length almost of two yards (deux metres), taking the 

 antennte into the admeasurement. The species 

 found in our latitudes resort during the winter to 

 the depths of the sea, and approach the shore only 

 on the return of spring. They give preference to 

 rocks or rocky situations. The females breed at 

 this season, and the eggs, which are small and very 

 abundant, are of a beautiful red colour, whence the 

 term cdial, which from this cause has been applied 

 to them. More males than females are captured, 

 although the latter are the most after the breeding 

 season. According to M. Risso, the females breed 

 a second time in August. These Langoustes are 

 spread in all the seas of all the temperate and inter- 

 tropical zones, but especially in the latter. The 

 carapace is rough, bristling with spines, and pre- 

 sents anteriorly large spikes, directed forwards and 

 more or less numerous. The general colours pre- 

 sent an agreeable mixture of red, green, and yellow ; 

 and the tail is often marked with transverse bands 

 or spot.^, sometimes in the form of eyes disposed in 

 rows. The flesh, especially that of the females be- 

 fore and during the laying season, is much es- 

 teemed.' The genus Palinurus presents the foHow- 

 ing characters: — the carapace is nearly straight, 

 armed at its anterior border with two stout horn.s, 

 which advance above the eyes and base of the an- 

 tennae, and on each side below the eyes there is a 

 horn more or less developed. The carapace is co- 

 vered with spines; the eyes are large; the internal 

 antennffi are long, and end in a bifid joint. The 

 external antennae are stout, and of great length, 

 often far exceeding that of the body : the jaw-feet 

 are small. All the limbs end in simple joints. The 

 abdomen is large, and has four pairs of false 

 feet. The caudal tin, formed by the seventh ab- 

 dominal ring and the appendages of the preceding 

 ring, is very large, and to a great extent of a flexible 

 consistence. 



Fig. 3221 represents the under surface of the Sea 

 crayfish, or Langouste (Palinurus vulgaris). Fig. 

 3222 is the Palinurus vulgaris, the Sea crayfish, or 

 crawfish, so abundant in the London markets. It 

 is in very general use as an article of diet, and cer- 

 tainly is excellent, but \<i flavour and tenderness of 

 fibre is far inferior to the lobster. It occasionally 

 weighs from ten to fifteen pounds. In the female 

 there is a sort of spur or tooth at the extremity of 

 the last joint but one of the posterior limbs ; it does 

 not exist in the male. 



A beautiful species of the present genus, Palinurus 

 ^ttatus, Fig. 3223, is found in the seas of the An- 

 tilles. The colour is green with many circular yel- 

 lowish spots ; the penultimate joint of the limbs is- 

 •triated longitudinally with green and yellow. 



M. Milne Edwards informs us that there is in the 

 Paris Museum a limb, apparently the third, of 

 extraordinary piopoitions, belonging to a species of 

 Palinurus ; it is more than two feet in length (French 

 raea-sure), and proves the existence of a gigantic 

 crustacean of this genusi, as yet unknown to natural- 

 ists. The specimen in question came from the Isle 

 of France. 

 A very interesting group or family of Macrura 



are termed Thalassinians by M. Milne Edwards, 

 from the typical genus Thalassina. They appear to 

 be burrowing in their habits, and are all of small 

 size, living on sandy shores. M. Milne Edwards 

 arranges them between the Scyllarians and Asta- 

 cians, but some of the genera, in which there are 

 accessory branchial appendages affixed to the false 

 feet, seem to approximate towards the Stomapods. 



They are all remarkable for the length and slen- 

 derness of the abdomen ; the anterior pair of limbs 

 are furnished with chelae, and sometimes the second 

 pair are terminated by pincers. The carapace is 

 small and compressed laterally, generally advancing 

 in front in the form of a small rostrum, but some- 

 times this is wanting. The eyes are minute. The 

 internal antennae are terminated by two multiarti- 

 culate filaments ; the external antennae by a single 

 filament. As we have said, the respiratory appa- 

 ratus varies. Sometimes, besidesthe thoracic bran- 

 chiae, there are additional branchiae suspended under 

 the narrow slender abdomen, and attached to the 

 false feet. Upon this difference M. Milne Edwards 

 divides the Thalassinians into two sections, viz., 

 Cryptobranchids and Gastrobrancluds. In the Cryp- 

 tobranchids there are no accessory abdominal bran- 

 chiae, and the true branchiae in the thoracic cavities 

 are united in the manner of a brush. All the spe- 

 cies of which the habits are known burrow to a 

 considerable depth in the sandy bed of the sea. 



To this section belong the genera Axia, Gebia, 

 Thalassina, and Callianassa. 



In the genus Axia the carapace is much com- 

 pressed, and terminated anteriorly by a small trian- 

 gular rostrum. The ocular peduncles are small and 

 cylindrical. The anterior limbs are compressed and 

 terminate in a well-formed claw : the next pair of 

 limbs have small pincers; the rest are simple. 

 There are five pairs of false abdominal feet. 



Of this genus only one species appears to be known, 

 namely, the Axia Stirhynchus, Fig. 3224. It is 

 about three inches in length, and inhabits the coasts 

 of France and England : a. one of the internal an- 

 tennae ; ft, one of the external antennae. 



In the genus Gebia the anterior rostrum of the 

 carapace is triangular, and sufficiently large to cover 

 the eyes almost entirely. The internal antennae are 

 short ; the external antennae slender. The anterior 

 limbs are narrow, and terminate in a subcheliform 

 manner. The other limbs have simple termina- 

 tions. The abdomen is long, narrower at its base 

 than towards its middle, depressed and terminated 

 by alargefiu; the tour lateral blades are Ibliaceous 

 and very wide. The first abdominal ring has two 

 pairs of small filiform false feet ; the lour next seg- 

 ments give origin to three pairs of false natatory 

 feet, composed of a short and stout peduncle, and 

 two oval blades with ciliated edges. 



The Gebia stellata. Fig. 3225, is an example ; it 

 is about an inch and a half in length, and is a 

 native of the coasts of England : a, one of the 

 internal antennae ; b, the base of one of the external 

 antennae. 



In the genus Thalassina the carapace is short, 

 narrow, and elevated, and furnished in front with a 

 triangular rostrum. The peduncles of the eyes are 

 small and cylindrical. The internal antennae have 

 two short, slender filaments ; the external anfenuce 

 are small and slender. The first pair of limbs are 

 rather robust and subcheliform ; the moveable claw 

 antagonizing with a toothlike process of more or 

 less strength on the penultimate joint. An approxi- 

 mation to this form is displayed by the second pair 

 of limbs, the penultimate joint being large and 

 ciliated. The abdomen is long and narrow : slender 

 false feet are attached to the four middle rings. The 

 terminal fin is small ; the two lateral blades fur- 

 nished by the preceding or sixth ring are small and 

 nearly linear. 



Our example is the Thalassina scorpionoides, 

 Fig. 3220, from the coasts of Chile. It i*; of a 

 brownish colour, and measures about six inches in 

 length. Its abdominal segments remind us of the 

 segments of a Scolopendra, or centipede. 



In thegenus Callianassa the general characters ap- 

 proximate to those of Thalassina, but the two anterior 

 limbs, which have both true chela;, ditt'er from each 

 other very greatly in size, as we have already seen 

 in the Hermit-crabs (Pagurus). The lateual caudal 

 plates are large. 



One species, Callianassa subterranea. Fig. .3227, 

 is found on the sands of the sea-shore, washed up 

 by the tides, on the French and English coasts: 

 a, one of the internal antennte ; ft, the base of one 

 of the external antenna; ; c, the right or large chela. 

 M. Milne Edwards record's another species, Callia- 

 nassa uncinata, and observes that the C. major of 

 Say appears to differ from both. 



VVe now turn to the Gastrobranchid section, 

 which, besides tlioracic brancbiie, have respiratory 

 appendages fixed to their abdominal false feet, a 

 point in which they exhibit an analogy with the 

 crustaceans of the order Stomapoda. The type of 

 this section, according to Milne Edwards, is a small 



, crustacean, to which he gives the generic name of 



Callianidea, and which he characterizes as follows : 



Body very delicate, slender, and elongated; cara- 

 pace hardly a third of the length of the abdomen, 

 and not covering the last thoracic ring, compressed 

 and rather elevated, its lower border applied ex- 

 ! actly against the base of the four first pairs of feet. 

 No rostrum; and the anterior border of the carapace 

 notched on each side of the median line for the re- 

 ception of the base of the eyes, whose peduncles are 

 I very short, and formed as in the Callianassa;. Four 

 antennae, slender and inserted nearly on the same 

 transversal line ; the first pair terminated by two 

 filaments nearly equal in length, one of which how- 

 ever is the largest, and slightly convex towards the 

 end. Appendages of the mouth very small, occu- 

 pying but little space; mandibles hardly differing 

 from those of Callianassa; valvular appendage of 

 the second pair of jaws very small ; external jaw- 

 feet slender and pedilbrm, their second joint fur- 

 nished internally with a row of dentiform tubercles 

 covered with hairs, and with their three last joints 

 very much elongated. Sternum linear throughout 

 its extent. First pair of feet long, and one of 

 them very stout, with the terminating hand very 

 large, and nearly of the same form as in Callianassa, 

 except that the carpus is smaller. I'lie two suc- 

 ceeding pairs of feet are small and flattened ; the 

 fourth pair nearly cylindrical, and their basilary 

 I joint very much enlarged. Filth pair nearly as 

 large as the fourth, and terminating in an imperfect 

 I rudimentary claw. Abdomen composed as ordi- 

 t narily of seven segments, nearly of the same size 

 throughout, and carrying beneath five pairs of false 

 feet; of these the first are reduced to a simple nar- 

 row blade slightly ciliated at the end, but the four 

 succeding pairs have a very remarkable conforma- 

 tion. A peduncle is to be distinguished, and 

 three terminal lamina;, two of which are very large, 

 and one very small, on the edge of the preceding 

 ones ; all round the border of the great larninie a 

 kind of tufted fringe is found, composed of a row of 

 cylinders, each of which gives origin to two smaller 

 filaments, which again in their turn are biluicated 

 nearly in the same manner as the branchial fila- 

 ments of the Squillae are divided. The five blades 

 of which the caudal fin is composed are wide and 

 rounded. The thoracic braiicluiE are enclosed as 

 ordinarily in the carapace, and are each composed 

 of cylinders ranged in parallel order on a stem, 

 nearly as in the lobsters, only these organs and fila- 

 ments are less numerous, and the branchiae them- 

 selves very small. There are only ten on each side 

 of the body. (M. E.) 



Fig. 3228 represents the Callianidea typa greatly 

 magnified. Its length is about ten lines; it was 

 found by MM. Quoy and Gaimard on the coasts of 

 New Ireland : a, one of the internal antennae, bifid 

 and plumose ; ft, one of the external jaw-feet ; c, 

 exlreuiily of one of the posterior feet ; d, one of the 

 first pair of tlie abdominal lalse feet ; e, a false foot 

 of one of the succeeding pairs; /, the marginal 

 fringe of the latter feet. Tliese figures are all mag- 

 nified. 



We may here allude to an anomalous form of the 

 Macrurous Decapods, found only in a fossil state, 

 and which, as Desniarest observes, appears to con- 

 stitute asection by itself. The generic title proposed 

 by this zoologist is Eryon, with the following cha- 

 racters : — External antennae short (one eighth of the 

 total length of the body including the tail), seta- 

 ceous, provided at their base with a rather large 

 scale, which is ovoid and strongly notched on the 

 internal side ; intermediate anteiiuii; setaceous, bifid, 

 much shorter than the external ones, and having 

 their filaments ecpial. Feet of the first pair nearly 

 as long as the body, slender, linear, not spinous, 

 terminated by very long and narrow chelae, with fin- 

 gers little bent, but sliglil ly inflected inwards ; carpus 

 short ; feet of the other pairs also slender, and 

 these of the second and third pairs terminated 

 with pincers, like the feet of the crawfishes (ecre- 

 visses). Carapace very much depressed, wide, 

 nearly square but little advanced anteriorly, pro- 

 foundly notched on its latero-anterior borders. 

 Abdomen rather short, foumed of six articulations, 

 of which the four intermediate ones have their 

 lateral borders prolonged in angles, well detached, 

 as in the crawfishes, (/'audal tin formed of five 

 pieces, of which the two lateral are entire, rather 

 large, a little rounded on the internal side, and the 

 three middle ones triangular and elongated, especi- 

 ally the intermediate mie. 



According to M. Desmarest, it is to the Callia- 

 nassa;, the Thalassinae, the Gebiic, and the Axia;,' 

 that Eryon bears relation. Nevertheless it has not, 

 he observes, the habit of any of them. Its short 

 depressed carapace, and its little elongated abdo- 

 men, approximate it to Scyllarus, but its internal 

 antenna; with short peduncles, its external setaceous 

 antenna;, and its great anterior didactylous feet, 

 widely separate it from that genus. It cannot be 

 confounded with Palinurus, which has the external 



