EKICHTlirS. 



ERICHTHUS. 



the antenna, nd attoated toward* the midtlle of the carapace. The 

 up|*r lip U Urge, demicircular, and projecting. The mandible* are 

 directed downward* a* in the Sg <ttike, and there a a large denticulated 

 tooth aad a prolongation equally dentilated on it* edge, which mount* 

 toward* the (tomarh, but the palpiform *tem U null or rudimentary. 

 Behind the mandible* are found a large inferior bilobated lip, and 

 then two pair* of jaw*, the form of which in the name a* in the 

 .S0 uillidm. The appendage* that correspond to the jaw-feet of the 

 flnt pair present nothing remarkable ; they have the form of a long 

 and slender (tern, and, a* in the other crustacean* of this family, do not 

 Mem to form a part of the buocal apparatus. The members of the 

 fallowing pair are very large, and constitute prehensile feet (pates 

 ravisseoM*), exactly .imilar to thoe of the SjviUa ; their penulti- 

 mate articulation i* enlarged and vpinous towards the base, and their 

 terminal claw is short, and armed with spiniform teeth on the 

 prehensile edge. The feet of the three following pairs are inserted 

 on a transverse curved line immediately behind the prehensile feet, 

 and are habitually applied against the mouth exactly as in the 

 &(*illid<r; each of these carries at its base a flattened disc-like. 

 Teatcle, and i* terminated by an oval cheliferous manus. The three 

 last thoracic rings are complete, and free below the carapace, which 

 covers the first two. The three pairs of corresponding feet are of 

 moderate size, and formed a* they are in the SquMida, only their 

 last joint is not setiferous. The abdomen is large, and much 

 resembles that of the Squilkr, except that the last segment is much 

 larger, and habitually covers the members of the penultimate ring. 

 These last organs are composed, as iu the Squillfe, of a peduncular 

 joint, which prolongs itself inferiorly into a great lamina, and carries 

 two appendages inserted on its edges near its base. The internal 

 appendage consist* of a great ciliated lamina, and the external 

 one is composed of two joint*, of which the last is oval, and 

 the penultimate joint armed with spines on the external border. 

 The false feet suspended from the first five rings of tho abdomen 

 are large, and formed of a nearly square peduncular joint, and of 

 two great oval lamina; with ciliated edges; the internal lamina 

 bears on it* internal edge a small rudimentary appendage, and 

 the external gives insertion, near its base, to a large ramose 

 branch!*. 



M. Milne-Edwards, who founded this genus, and whose description 

 we have above given, considers that fyuHlericltttnu forms the passage 

 between the SquMa and the AVicA/Ai. 



It has only been found as yet in the Asiatic seas. 



The species (two only are recorded) are small. 



8. lyptu. Rostrum advancing beyond the peduncle of the internal 

 antenna); a great horizontal spine on the midoUe of the posterior 

 border of the carapace ; and, on each side, another and longer spini- 

 form elongation, springing from the angle of the carapace ; finally, a 

 rather strong point towards the middle of the lateral border of the 

 carapace, and another above the base of the external antennae. Claws 

 of the prehensile feet armed with four teeth (including the terminal 

 point). The last thoracic ring i* not covered with the carapace, 

 and the abdomen is very large. Its last segment is much longer 

 than it is wide, and armed with three pair of marginal teeth. 

 Length about 15 lines. Found iu the seas of Asia. (Milne- 

 Edwards.) 



The other specie* recorded by M. Milne-Edwards, S. tpinoiia, was 

 taken by M. Dussumier in the Uulf of Bengal. 



Krichthtu. Carapace very large, convex, and armed with spiniform 

 elongations. It entirely covers the bane of the ocular peduncles, as 

 well as of the antenna?, and extends backwards more or less far beyond 

 and above the abdomen, which is short and large. The eyes are large, 

 pear-duped, and are not carried on a slender and elongated stem, as 

 in the SqniUeridUki and Alimtr. The antenna; present nothing remark- 

 able, except that the stemlt-t (tigelle) of those of the second pair in 

 often rudimentary, and that those of the first ]>air are rather short. 

 The moath is formed in the same manner as it is in the < 4/m7/<rirA/A, 

 only the external jaw* are extremely small, and narrower. The jaw- 

 bat of the first pair are extremrly slender, and of moderate length ; 

 they are slightly enlarged toward* the extremity, and have a rudi- 

 mentary nail or cUw at the end. The prehensile feet are but little 

 developed ; their claw 1* nearly straight and without dentilations, and 

 the penultimate joint is slender, elongated, straight, and devoid of 

 spine*. The feet of the three following pairs are formed in the 

 same manner a* they are in SguiUtricklkui, but they are inserted 

 one after the other ; the flattened vesicle fixed at the baas of each 

 of these organ*, as well a* of the members of the two preceding 

 pair*, is very large. The thoracic feet of the last three pair* are 

 formed in the same manner as in &;ni77u and fytiilUricJulHu, but 

 are little developed, and sometimes want tho iitylifonn appendage ; 

 at other time* they an entirely rudimentary, and are only com- 

 posed of a small peduncle, terminated by two articulations nearly 

 like the false abdominal feet, but much smaller. The abdomen is 

 wide and short; the caudal fin which terminates it is disposed as 

 in .--./H.llrrirUhtu, and the false feet of the first pair nre large, and 

 terminated by two great oval lamina', on one of which is a rudimentary 

 bntnchia. 



M. Milne-Edwards, who gives the above characters, divides the nine 

 specie* into the following sections : - 



o. Specie* whose rostrum is very long, and passe* sensibly beyond the 

 internal antenna. 



Ex. . vitreut (Smerdit rulyarir, Leach). 

 Atlantic Ocean. 



Locality, tho Southern 



EritUlua rilrriu. 



ft. Species whoso rostrum is of moderate length, and passes l*-\ .>n.l 

 the peduncle of the internal antenna; without attaining to the 

 extremity of those appendages. 



Ex. E. aitnatut (Smerdit armala, Leach). Locality, coasts of 

 Africa. 



y. Species having the rostrum extremely short (not passing beyond 



the peduncle of the internal antenna.'). 

 Ex. t\ Ifurauccllii. Locality, Gulf of Bengal. 



ErichthuM Dttraticellii. 



A lima. Carapace narrow, straight above, if not altogether so 

 behind, where it often presents a sudden roof-like elevation ; rostrum 

 straight and styliform. The anterior angles of the carapace constitute 

 two acute spines directed forwards ; the posterior angles are also pm 

 longed into the form of points directed backwards on each side of tho 

 abdomen. Finally, the lateral borders of the carapace are nearly 

 straight. The opthnlmiu and antennular rings are not hidden under 

 the carapace as in AVi'cAMiw, but are seen uncovered under the rostrum. 

 The eyes are carried on slender long cylindrical peduncles directed 

 outwards. There is nothing particular about the antenna,*. The 

 mouth is situated very far from the front, towards the posterior third 

 of the lower surface of the carapace ; the upper lip, the mandibles, 

 the lower lip, and the two pairs of jaws, have the same form as iu 

 ErichlJita and SquMtnchlhiu. The thoracic feet arc formed also iu 

 the same manner as in KrlrMhtu, hut the three pairs of nn -iul T.S 

 which follow the prehensile feet are more approximated to the mouth, 

 as in the Squitl<r. The posterior border of the carapace is ordinarily 

 notched, so as to leave uncovered the two lost thoracic rings, an.l tin- 

 abdomen is narrow and elongated. The falso feet are large, but uru 

 in general completely devoid of bronchia; : sometimes vestiges of these 

 organs are found upon the abdominal members of the first pair, ami 

 at other times they are represented by a small pediculated tubercle 

 fixed to the external blade of these appendage*. Finally, tho cou- 



.Ilima hyalina. a, natatory ventral appendage mngniiinl. 



formation of tho species of caudal fin formed by the lost abdominal 

 segment and the false feet of the sixth ring are entirely the sumo as 

 in Krifhihiu. M. Milne-Edward*, whose description wo have given, 

 states tL.it the Alima bear an extremely strong resemblance to the 



