44 THE VOYAGE OF H.M.S. CH ALLEN GEE. 



Habitat. — The ahove described specimen was taken in the Pacific Ocean, south of the 

 Fiji Ishinds. 



Station 174u, August 3, 1874; kt. 19° 7' 50" S., long. 178' 19' 35" K; depth. 

 tilO fathoms; coral mud; bottom temperature, 39°"0. 



9. Gnathophansia zoea, Willemoes-Suhm (PI. VI. figs. 6-10). 



Gnathophmisia zocn, Suhm, Trans. Linn. Soc. Lond. (Zool.), .ser. 2, vol. i. p. .32, pi. ix. figs. 2-15, 



pi. X. fig. 4, 1875. 

 Gnathophauxia zoea, G. 0. Sars, Preliminary Xotices on the Challenger Schizopoda, No. 9. 

 Gnathoj}hmisia zoea, A. Jlilne-Edwards, Receuil de Figures de Crustaces nouveaux ou peu 



connus, V livraison (two last plates), Paris, April, 1883. 



Specific Characters. — The body not so .slender as in the two last species. 

 Carapace rather large, completely covering whole of trunk, and produced behind as a 

 very large dorsal spine, in some specimens jutting out even beyond the fourth caudal 

 segment. Posterior margin of carapace in upper part coarsely denticulate, the denticles 

 continued along the lateral edge of the dorsal spine. Both lateral keels distinct. 

 Rostrum very elongate, even exceeding the carapace in length, and strongly denticulate 

 throughout. Supra-orbital and antenna! spines well marked and considerably projecting ; 

 brauchiostegal spines wanting. Caudal segments slightly keeled above, and produced 

 posteriorly into small spines; posterior lappet of epimera acutely pointed. Antenntd 

 scale with spine of outer corner somewhat projecting beyond the terminal lobe, and 

 slightly denticulate at the outer edge. Telson of the usual form, the apical spines 

 connected by a thin serrate lamella. Length reaching 70 mm. 



Remarks. — This form has been well described and figured by the late Dr. v. Willemoes- 

 Suhm in the above cited treatise, and several figures of the same species have also been 

 prepared by Professor A. Milne-Edwards on two plates, belonging to a collection of drawings 

 of Crustacea, recently published by that author. It may readily be distinguished from 

 the preceding species by the very strong development of the dorsal spine, from which 

 character, indeed, the specific denomination ''zoea" has been derived, this name, as 

 is well known, being generally applied to a larval stage of Brachyura, prominently 

 distinguished by the presence of a large dorsal spine issuing from the dorsal surface of 

 the carapace. 



Description. — No less than five specimens of this striking form were procured on the 

 Challenger Expedition from difi"erent localities. Of these, two are females and three 

 males, aU agreeing very closely in all essential characters. The largest of the speci- 

 mens, a male, attains a length of about 70 mm. 



The form of the body (see figs. 6, 7) is somewhat more robust than in the three 

 preceding species, the anterior division being rather more dilated, and the tail not so 

 slender. 



