86 THE VOYAGE OF H.M.S. CHALLENGER. 



the soft parts, I have been unable to ascertain by dissection whether there exists any 

 corresponding deficiency as regards the right ovary. The previously known species of this 

 characteristically deep-water genus are Parapagurus pilosimanus, S. I. Smith ( = Eupag- 

 urus jacohii, A. Milne-Edwards), which has been taken in abundance ofi" the east coast 

 of the United States, by the Fish Commission and Coast Survey vessels, and Parapag- 

 urus dimorphus (Studer) recorded below. 



Parapagihrus dimorphus (Studer) (PI. X. fig. l). 



Eupagurus dimorphus, Studer, " Gazelle " Crust., Abhandl. d. k. Akad. d. Wiss. Berlin, p. 24, 

 taf. ii. figs. 11-12, 1883. 



Habitat. — Station 135c, ofi" Nightingale Island, Tristan da Cunha; depth, 110 

 fathoms. Several specimens of small size, in shells of Murex (Pseudomurex) aedonius, 

 Watson, taken along with Eupagurus tristanensis. 



Station 142, ofi" the Agulhas Bank; depth, 150 fathoms; bottom, sand. A large 

 number of specimens (including several females with ova), inhabiting shells which have 

 become almost completely absorbed by an investing Epizoanthus. 



Station 145 or 145a, ofi" Marion Island; depth, 140 or 310 fathoms; bottom, 

 volcanic sand. A single specimen in a very imperfect state of preservation. 



Station 311, off Port Churruca, Patagonia; depth, 245 fathoms; bottom, blue mud. 

 A female with ova, in a shell of Pleurotoma acanthodes, Watson. 



In this species the eye-stalks are of considerable size and the corneae dilated, although 

 these organs are slender in all other known members of the genus. The sexual 

 dimorphism chiefiy manifests itself in the form of the right chelipede, which in the 

 female has the hand short and broad, with the dactylus (when closed) bent almost at a 

 right angle to the upper border, whereas in the male the hand is proportionately narrower 

 and the fingers are elongated and oblique. Dr. Studer has figured what is evidently an 

 old male, for the fingers of the right chela are represented as meeting only at the tip, 

 leaving a considerable intervening hiatus ; in none of the Challenger specimens is this 

 condition observable. The right chelipede has a prominent and acute dentate lobe on 

 its lower and distal margin, and a similar less extensive, though more pronounced, lobe 

 occurs in the same position on the carpus ; the lateral margins of the hand are sharp and 

 dentate. The ophthalmic scales are poorly represented, and a reddish band is still 

 visible on each lateral surface of the eye-stalk. The antennal peduncle extends to the 

 end of the eye-stalk, the external prolongation of the second joint is moderately long and 

 acute, and the third joint bears a prominent spinule on its inner surface ; the inner 

 margin of the acicle is distinctly spinose, and the fiagellum is faintly ciliated. The 

 terminal joint of the antennular peduncle is considerably shorter than the antennal 



