268 



Unlike other species of the genus, this species was found in the holes of a Holothurian 

 [Candind)^ in the Bay of Hakodadi (Japan). 



Finally there is a species, P. brevipes H. Milne-Edwards. Ann. Sc. Nat. (3), t. 20, 1853, 

 p. 220, from Madagascar, but this species does not seem to belong here (see p. 284 — 285). 



Tetrias Rathbun. 



1899. Tetrias Rathbun. Proc. U.S. Nat. Mus., v. 21, p. 607. 



The genus has been established on T. scabripes Rathbun, 1. c, p. 608, pi. 43, f. 12 — 14, 

 from Lower California. 



Alcock ^) places also ''Pinnixd" fischeri A. Milne-Edwards in the genus, but regards 

 the latter as merely a subgenus of Pinnixa. I cannot agree with him. The carapace in Tetrias 

 is much narrower, the transverse cardiac ridge, so commonly met with in Pinnixa, is altogether 

 absent, and the whole surface of the carapace, instead of being smooth and glabrous, is thickly 

 pubescent and granulate. In the e.xternal maxillipeds the propodus is not projecting beyond 

 the insertion of the dactylus, but both segments are inversely-triangular, especially the former, 

 widening distally and with a dense row of feathered hairs along outer and distal margin. The 

 walking legs are densely hairy; the second pair, not the third as in Pinnixa, is the longest, 

 the last pair is much reduced, spinous along posterior margin-, the dactyli of all the walking 

 legs are very short, nearly disappearing among the long setae of the propodites. 



I. Tetrias fischcri (A. Milne-Edwards). PI. 18, Fig. i. 



1867. Pinnotheres fischeri A. Milne-Edwards. Ann. Soc. Ent. France, t. 7, p. 287. 



1873. Pinnixa fischeri A. Milne-Edwards. Nouv. Arch. Mus. Paris, t. 9, p. 319, pi. iS, f. 3. 



1888. Pinnixa fiscJierii de Man. Arch. Naturgesch., Jhrg. 53. i., p. 385, pi. 17, f. 2. 



1900. Tetrias fischeri [Pinnixa [Tetrias] fischeri) Alcock. Journ. As. Soc. Bengal, v. 69, prt 2, 



P- 336. 



Stat. 181. Ambon. Depth 36 — 51 m. i cT, on reef. 



The figure of the whole animal, as given by Milne-Edw.\rds, does not agree with what 

 is found in the "Siboga" specimen. In the old example (a 9) the carapace is represented broader 

 than in my specimen"), in which the breadth is about 1.4 times the length, and neither the 

 setose covering of the whole animal nor the granulation of the carapace is correctly given, 

 unless it must be admitted, what is quite likely, that adult individuals rather considerably differ 

 from young ones. 1 



De Man examined both sexes and stated that in the cf nearly the whole carapace is 

 finely granulate and tomentose, with exception of some few regions (hind part of mesogastric 

 and anterior portion of cardiac area, with its surrounding parts), which are smooth and glabrous. 

 In my specimen, which is smaller, the gastric region is, like the rest of the surface, granulate 



i) Journ. As. Soc. Bengal, v. 69, prt 2, 1900, p. 336. 



2) Mn.NE-EDWARDs' measurements are in some way quite erroneous: the width of the carapace is said to be 15 mm. (by 

 typographical enor: cm.), the length 58 mm. (! ) 



