1073 



GONIODUS. 



GONOPLACID^E. 



1074 



0. donalis, Brown, 

 ft. notuttu, Phil, 

 ft. excaratiu, Phil. 

 (f. erpantus, Buck, 

 ft faicicviatus. 

 G. foraminosus, Phil. 

 If. iMioni, Phil, 

 ft Gilberttoni, Phil, 

 ft granonu, Portl. 

 ft Hmtlowi, Sow. 

 ft. implicatut, Phil, 

 ft. intercottalis, Phil, 

 ft. intermedia*, Brown, 

 ft. jugomw, Brown, 

 ft Kenyoni, Brown, 

 ft tou*. 

 ft. Litteri, Sow. 

 ft. Lonythorni, Brown, 

 ft. Loonoyi, Philips. 

 ft. mixonottu, Philips, 

 ft. minutussimu*, Brown. 

 ft. misotobut, Phil, 

 ft mutabilit. 



ft. nitidus, Phil, 

 ft. obtusws, Phil, 

 ft. pamdoxicus, Browri. 

 ft. pan-ua, Brown, 

 ft paucilobus, Phil, 

 ft platylobut, Phil, 

 ft. proteus, Brown, 

 ft reiiculatus, Phil, 

 ft rotiformu, Phil, 

 ft serpentinui, Phil, 

 ft. Smithii, Brown, 

 ft spharicus, Sow. 

 ft. sphceroidalis. 

 ft. spirorbis, Phil, 

 ft splendidus, Brown, 

 ft itenolobus, Phil, 

 ft striatut, Phil, 

 ft striolatus, Phil, 

 ft. fubiulcatus, Brown. 

 ft Iruncatus, Phil, 

 ft. undulatut, Brown, 

 ft. t'e'ca, Phil. 



ft. rittiyer, Phil. 



DEVONIAN GROUP. 



l-'oniatitci biferui, Phil. ft fincaris, Miinst. 



ft carionaritts, Sow. ft mixolobus, Phil, 



ft crenittrta, Phil. ft. terpentinns, Phil. 



ft. excaroltw, Plul. ft. tpiralit, Phil, 



ft. globotut, Miinst. ft. tpirorbii, Phil. 



ft. t'nc07W<ajM, Phil. ft Irarutioritw, Phil, 



ft intiyaii, Phil. ft rinctum, Sow. 



HDXIODUS. [SQI-ALID-F..] 



OONIO'GXATHUS, a genus of Fossil Cycloid Fishes, from the 

 London Clay. (Agassiz.) 



GONIO'PHORUS (Agassiz), a genus of Fossil Schinida, from the 

 Greenaand. (Morris, Catalogue.) 



GONIOPORA. [MADREPOR.KA.] 



GONOPLACID.<E, Gonoplaciant, an order of Brachyurous Crusta- 

 ceans, whose carapace is either square or rhomboidal, and much 

 wider than it is long. The posterior border, measured between the 

 base of the fifth pair of feet, equals, nearly always, the half of its 

 transverse diameter; while in the tribe of Ocypodians, as well as in 

 the Cyclomctopes, and the greater part of the Oxyrhynchi, the length 

 of this border is only about a fourth of the greatest width of the 

 carapace. The front is but little inclined, and very wide ; it does 

 not curve downwards so as to unite itself throughout nearly its whole 

 width to the epistome, as in the Ocypodians, and it is equal to two- 

 thirds of the buccal frame measured at the point of its greatest width. 

 The in ill. 11- peduncles are in general very much elongated and rather 

 small ; their length often equals five or six times that of their dia- 

 meter, and the cornea which terminates them is always small. The 

 external angle of the orbit ordinarily occupies the lateral extremity 

 of the carapace. The internal antenna) are always horizontal, quite 

 exposed, and lodged in little pits (fossettes) distinct from the orbits. 

 The external antennae are disposed nearly as in the Ocypodians. The 

 epiatome is often placed at some distance behind the inferior orbitary 

 border, a character which is always met with jn the Cyclometopes, and 

 exists but rarely in the family of Catametopes. The buccal frame is 

 generally wider at its anterior border than at its posterior part, and 

 the fourth joint of the external jaw-feet is inserted nearly always at 

 the internal angle of the preceding articulation. The sternal plastron 

 is very wide, aud is sometimes perforated for the passage of the intro- 

 minive male organs (les verges) ; but in general these organs are 

 Inserted, aa in other families, at the basilary joint of the posterior 

 feet, and are lodged in a small transversal canal hollowed in the 

 Hternal plastron at the point of union of its two last segments, a canal 

 which serves them for a sheath till they arrive under the abdomen. 

 The length of the anterior feet varies ; it is sometimes very consider- 

 able, and those of the third or fourth pair, which are always the 

 longest among the eight last, have nearly two and a half times the 

 length of the post-frontal portion of the carapace : they are all slender, 

 and terminated by a styliform tarsus. The abdomen of the female is 

 very wide, and covers nearly the whole of the sternal plastron ; but 

 that of the male, on the contrary, is very narrow, and instead of 

 extending to the basilary joint of the posterior feet, loaves exposed 

 a considerable portion of the sternal plastron between its external edge 

 and the base of those feet. In the greater number of cases its second 

 ring is entirely linear, while the others are sufficiently well developed. 



Such is the character given to this tribe by M. Milne-Edwards, who 

 placet) it between the Ocypodians and the Grapsoidians, and divides 

 it into the four following genera : 



Pteudorhombila (Milne-Edwards). M. Milne-Edwards states 

 that the crustacean which is the type of this new genus is very 

 remarkable, inasmuch as it holds a middle place between the Cance- 

 rian and the Gonoplaxes. The form of its carapace approaches that 

 of the Panopes, and of some other Ciuicerians, for it is slightly arched 

 in front, and between the orbits and the" lateral borders a considerable 



HAT. HIST. DIV. VOL. II. 



portion of its contour is curved backwards after the manner of the 

 latero-anterior border of tha carapace of the Cyclometopes ; but never- 

 theless its general form is that of a rhomb, and its posterior border 

 occupies more than the third of its diameter. The body is very 

 thick, and much elevated anteriorly. Front nearly horizontal, and 

 divided into two truncated very large lobes. Eyes, antennae, epis- 

 tome, and external jaw-feet, presenting the same disposition as in the 

 Crabs. Sternal plastron much wider than long, and very strongly 

 curved from before backwards; at its posterior part, which is very 

 wide, may be remarked on each side, in the male, a canal of consider- 

 able calibre, which lodges the intromissive organs, the origin of which 

 may be seen at the base of the posterior feet. The anterior feet are 

 very strong, and very long in the male ; the succeeding feet present 

 nothing remarkable, except that those of the form of the abdominal 

 of the same length as those of the third pair, second pair are nearly 

 rather shorter than the following ones. The and that these last are 

 appendages differs but little from the form of those of Xanthus. 



P. quadridtntata. Length about 2 inches ; colour rosy. Locality 

 unknown. 



M. Milne-Edward adds that the crustaceans figured by De Haan 

 under the name of Cancer (Curlonotiis) longimanus (' Fauna Japonica," 

 Crust., pi. vi. fig. 1) appear to him to come very near the preceding 

 species ; but as the description was not published, he could not 

 pronounce upon their identity. 



Gonoplax (Leach). Carapace more than one and a half times as 

 wide as it is long, and rather strongly narrowed backwards; the 

 fronto-orbitary border extends the whole of its width, and the front 

 itself is lamellar, slightly inclined, and terminated by a straight border. 

 The ocular peduncles equal more than a third of the width of the 

 carapace ; they are of medium size, and present no notable swelling 

 at their extremity. The internal antenna: are large and of ordinary 

 form ; the basilary joint of the external antennas is small and cylin- 

 drical like the following ones, and their terminal stem is very long. 

 The epistome is much less advanced than the lower border of the 

 orbit ; the buccal frame is much wider than it is long, and a little 

 narrowed backwards ; the form of the external jaw-feet is the same as 

 in the crabs. The disposition of the sternal plastron is nearly the 

 same as in Paeudorhombila, but it is to be remarked that the trans- 

 versal canal which lodges each of the intromissive organs is not 

 completely shut below. The anterior feet are extremely long and 

 nearly cylindrical ; those of the second pair are longer than the 

 second or the third; and those of the last pair are nearly of the same 

 length as the second. The abdomen of the male presents seven distinct 

 joints, like that of the female. 



ft. rhomboides. M. Milne-Edwards remarks, that M. Latreille 

 believed that this species could not be distinguished from G. angulata, 

 and says that perhaps it may be only a variety ; but he at the samo 

 time retains it as a species, and points out certain differences between 

 it and ft. anyulita. Length about an inch ; colour yellowish mingled 

 with red. 



Gonojilax rhoiitboides, 



It inhabits the Mediterranean and the Ocean, and keeps among 

 rocks at considerable depths, and seems to live solitary. According to 

 M. Risso it swims with facility, and rises often to the surface of the 

 water without ever coming out. 



It feeds on small fish and radiated animals. 



Professor Bell, in his 'British Crustacea,' says ft. angulata is a 

 British species, and states his conviction that ft. rhomboidet is only a 

 variety. 



3 /. 



