REPORT ON THE CRUSTACEA MACRURA. 429 



Habitat.— Station 137, October 23, 1873; lat. 35° 59' S., long. 1° 34' E. ; depth, 

 2550 fathoms ; bottom, red clay ; bottom temperature, 34°'5. One female (?). Dredged. 



Station 300, December 17, 1875 ; lat. 33° 42' S., long. 78° 18' W.; west of 

 Valparaiso ; depth, 1375 fathoms ; bottom, Globigerina ooze ; bottom temperature, 35° - 5. 

 Female (?). Trawled. 



The specimen unfortunately is very imperfect, but the form of the rostrum is not 

 unlike that of Sergestes spiniventralis (PI. LXVII. fig. 5). It consists of a short fine 

 point projecting horizontally for about one-fourth the length of the ophthalmopod, and 

 is dorsally furnished on the crest with a small tooth. The carapace generally is soft and 

 flexible, particularly on the lateral walls. 



The pereion has the pleural walls of each somite longitudinally divided as in Sergestes 

 prehensilis. 



The pleon is dorsally smooth, the first three somites are subequal in length, whUe the 

 fourth is rather shorter than the third, and the sixth is subequal in length to the fourth 

 and fifth together, and is laterally compressed and deeper than the preceding somites; on 

 the dorsal surface it is armed posteriorly with a small projecting tooth. 



The telson is about one-half the length of the sixth somite, laterally depressed near 

 the base and tapers to the extremity, which terminates in three points, the middle being 

 the longest. 



All the appendages are lost or broken off short, excepting the pleopoda and the 

 ophthalmopoda which are about one-fourth the length of the carapace, and have the 

 ophthalmus not of larger diameter than the stalk. 



The antennas are broken off just beyond the extremity of the ophthalmopoda. 



The mandibles carry a slender Particulate synaphipod that reaches to the extremity 

 of the ophthalmopoda, and has the inferior margins fringed with long hairs ; the margin 

 of the psalistoma is smooth. The metastomata are well developed and of a bat-shaped 

 form, and the succeeding oral appendages correspond with those of Sergestes pre- 

 hensilis. 



The gnathopoda and pereiopoda are all lost, being broken off short at the coxal joint. 



The pleopoda are perfect, the first pair being single-branched as in females, and the 

 others biramose. The posterior pair, which forms the lateral rami of the rhipidura, is 

 broken off at half its length, so that the form cannot be determined. 



Observations. — The species of this genus mostly live within a hundred fathoms of the 

 surface, but there is every reason to believe that this one resides near the bottom, it 

 having been taken in the same haul together with the rhipidura of a specimen of 

 Gnathophausia ingens and one of Gennadas intermedins. 



The branchiae, as well as could be observed, consist of a series of nearly circular discs 

 attached to a common stalk, somwhat like those figured on PI. LXV. fig. 3. 



