REPORT ON THE CRUSTACEA MACRURA. 



727 



The plcon has the third somite dorsally carinated and armed in the median line with 

 a strong tooth, the fourth and fifth somites with a minute point, and the sixth unarmed. 



The telson is long, narrow and tapering. 



The ophthalmopoda are a little shorter than the longest style on the rostrum, and 

 furnished with a protuberant ocellus. 



The first pair of antennas has the outer flagellum very stout at the base and 

 rapidly tapering to the apex. 



The second pair of antennae has the scaphocerite half as long as the first pair of 

 antennas. 



The second pair of gnathopoda is robust. 



The first pair of pereiopoda is robust and chelate. The second pair is more 

 slender than the first and chelate. The third, fourth and fifth pairs are slender and 

 monodactyle, each carrying a well-developed basecphysis. 



The pleopoda are biramose, the posterior pair being longer than the telson. 



Habitat.— Station 13, March 4, 1873; lat, 21° 38' K, long. 44 u 39' W.| Mid 

 North Atlantic ; depth, 1900 fathoms ; bottom, Globigerina ooze ; bottom temperature, 

 36°"8. Two specimens, one male (?). 



The carapace is not quite one-fourth the length of the animal and has the fronto- 

 dorsal region elevated to a laterally compressed and very thin crest, the margin of 

 which is fringed with seven teeth ; the smallest tooth is the posterior, standing on 

 the gastric region, they gradually increase in size, the anterior two, especially the 

 most anterior, being long and styliform. Between the cardiac and genital regions 

 a transverse furrow traverses the dorsal surface. The orbit is not deep or clearly 

 defined ; the first antennal tooth is but a small point, and the second appears to be 

 absent or worn off, but from it a longitudinal ridge runs subparallel with the lateral, 

 proceeding nearly to the posterior margin of the carapace. 



The first somite of the pleon is short and smooth, and the second is also short- and 

 longitudinally furnished with a small carina. The third somite is dorsally longer than 

 the preceding two and elevated to a strong carina, that commences abruptly at the 

 anterior margin and posteriorly projects to a strong, laterally compressed tooth ; the 

 fourth is nearly as long and is dorsally furnished with a small carina that posteriorly 



