48 DE. W. T. CALMAN ON A COLLECTION OF 



wholly hehind the carapace, and is bent npon itself so as to form a deep pouch, open 

 only in front, while in Eapalocarcinus it is flexed nndcr the body in the manner usual 

 among the Brachyura. Among other differences the orbits of Cryptochirus are defined 

 externally by a strong tooth, and the basal joint of the antennules presents a serrate edge 

 anteriorly where that of Ilapalocarchms has only a stout dentiform lobe. 



In describing Hctpalocarcimis, Stimpson noted its resemblance to Pimwtheres in the 

 large size of the abdomen and the softness of the integument, and he stated that its- 

 systematic position was probably between Pinnotheres and Hymenosoma. Apart from 

 the two points mentioned, there seems to be little in the chai-acters of the species as now 

 described to suggest affinity with the Pinnotheridre, while the third maxillipeds are 

 widely different in type from aiiytbing found in that group. 



Heller expressed no opinion as to the systematic place of his Cryptochirus. 



A. Milne-Edwards, however, has described under the name Llthoscaptus paradoxus (in 

 Maillard's ' Notes sur I'lle de la Reunion,' 2™^' ed., 1863, ii. Annexe F, pp. 10-12), a 

 form which, as Paulson has already pointed out, is in all probability identical with, or 

 closely allied to, Heller's species. Tiiis genus was regarded by Milne-Edwards as 

 representing a new family, " Lithoscaptes," among the " Bracliyures anormaux." 

 He writes, " par sa region cephalothoracique le Lithoscapte se rapproche des Ptanines 

 plus que tout autre groupe de Decapodes." Special resemblances to the Paninidie are 

 said to exist in the structure of the antennal region and in tlie shape of the thoracic 

 sternal region, which is broad in front but much contracted between the bases of the 

 last two pairs of legs. It is not clear, either from Milne-Edwards's or from Heller's 

 accounts (supposing the two genera to be identical), in what way the antennal 

 region resembles that of the Raninidse, while the thoracic sternum is not contracted 

 posteriorly, at all events in the female Hapalocar chins. Heller describes the sternum 

 of CryptocJiirm as " ziemlich breit, langlich oval." The third maxillipeds are said by 

 Milne-Edwards to resemble a little those of Reniipes, but this resemblance appears 

 to consist merely in the absence of a conspicuoiis exopod. Milne-Edwards describes 

 the abdominal appendages as uniramous and as existing on the first four somites. 

 According to Heller there are only three pairs, and this agrees with our examination 

 of Hapalocarcinus. 



Paulson refers Llthoscaptus ( = Cryptochirus) to the Pinnotheridae, establishing for its 

 reception a new subfamily, which he designates Crypochirinai and defines as follows : — 

 " Cephalothorax convex, almost twice as long as broad. Inner antenna? without 

 fossettes and lying longitudinally. Basal portion of the outer antennae free. Third joint 

 of the outer maxillipeds considerably shorter than the second. Openings of the female 

 sexual organs on the sternum " (' Crust. Bed Sea,' Kiev, 1875, p. 72). 



While the characters of Hapalocarcinns, as now described, show clearly that it must 

 stand alongside Cryptochirus, they give little help towards settling the place of the two 

 genera in the system. The position of the female genital apertiu'es shows that they 

 must be placed among the true Brachyura, although there are some curiou.s resemblances 

 to individual genera of the Anomura. Thus the endopod of the third maxillipeds 



