68 THE VOYAGE OF II. M.S. CHALLENGER. 



Rostral hit us short, rather broad, convex. Scutal margin straight. 



Infra-median latus bour-glass-shaped, with the umbo at the constricted part. The 

 part above the umbo is triangular and large, that beneath it is also indistinctly tri- 

 angular but very small. 



Carinal tutus has much the same shape as in Scalpellurn vulgare; flat, with the umbo 

 at the base of the carina, where the two carinal latera of the right and left side almost 

 touch each other. The carinal margin is divided into two parts, a superior one which is 

 hollowed out, and a very short and slightly protuberant inferior one. The basal margin 

 is short, the lateral margin arched. 



Length of the capitulum, 13 - 5 mm. 



The peduncle is short (4 '5 mm.), curved, with the scales large and not numerous. 

 There are about eight longitudinal rows, each of which contain about seven scales. 



The only specimen of this species was found attached to the shell of an Opistho- 

 branehiate Gasteropod (JRissoa, sp. ?), and was collected at Station 235, June 4, 1875 ; lat. 

 34° 7' N., long. 138° 0' E.; depth, 565 fathoms ; bottom temperature, 3°'3 C; bottom, mud. 



Observations. — I failed to observe the complemental male of this species. I have not 

 been able to study the parts of its mouth and its cirri, as I was not at liberty to dissect 

 the only specimen which was collected. 



Scalpellurn insigne, n. sp. (PL VI. figs. 3, 4). 



Valves thirteen, imperfectly calcified, except those of the lower whorl which are per- 

 fectly calcified, covered by membrane which is clothed with spines. Carina with a flat 

 roof and the umbo seated at or close to the apex. Calcified portion of the upper latus 

 semi-lunar in shape. Peduncle short. 



This species is represented by a single specimen only ; in many respects it comes near 

 to Scalpellurn japonicum. 



Capitulum consisting of thirteen valves, clothed by a thin chitinous membrane 

 covered with numerous very small hairs. The form of the capitulurn is elongate-oval. 

 Extremely characteristic is the imperfect calcification of the valves, and especially of the 

 tergum, scutum, and upper latus. These are separated from each other and from the 

 carina by broad chitinous interspaces. 



Scutum elongate, almost triangular. Its greatest breadth is near the inferior 

 extremity ; its length is only twice this breadth. The umbo is at the apex, which projects 

 over the tergum. The occludent margin is slightly arched. Of the two triangular parts 

 into which the scutum in other species of the genus is divided by a ridge, only one (the 

 occludent one) is calcified, the other is only represented by membrane. 



Tergum triangular, with the margins almost straight. The calcified part has the form 

 of a fork, and consists of two segments, — an occludent and a carinal segment of nearly 

 ccpial width, the point of junction being the apex of the valve. 



