12-4 THE VdVAci: OF E.M.S. CHALLENGER. 



Scalpellum peronii, Darwin, and Scalpettum mllosum, Darwin, to the much more rudi- 

 mentary state of the males in Scalpellum regium, Scalpellum darwinii, &c. The surface 

 of the male is clothed with rows of very minute spines. 



Scalpellum novce-zelandice, n. sp. (PL V. figs. 7, 8). 



Surface of the valves covered by a very thin chitinous membrane. Valves thirteen. 

 Carina simply bowed, with a flat roof and with the umbo at the apex. Upper latus 

 quadrangular or rather pentagonal, the lower edge being truncated. Valves of the 

 lower whorl well-developed. Infra-median latus elongate, quadrangular. Carinal latus 

 large, elongate, with the umbo near the base. Peduncle short. 



This little species is represented by a single specimen only. In general shape it much 

 resembles Scalpellum Jlavum, yet I think it must be considered as specifically distinct. 



The capitulum is elongate, flat, and consists of thirteen valves. The valves are not 

 very close to one another, but are separated by narrow chitinous interspaces. A thin 

 chitinous membrane covers the capitulum and adheres to its surface. Only here and 

 there the calcareous surface of the valves appears. The elongate form of the capitulum 

 is caused by the length of the other valves as well as by those of the lower whorl. 



The scat u m is quadrangular, not quite twice as long as broad. The umbo is at the 

 apex, which is slightly produced and recurved, and covers a small part of the tergum. 

 The occludent margin is arched, the basal margin also ; the lateral margin is not distinct, 

 the valve being covered here by the free edge of the upper latus. 



The tergum is triangular, the umbo is at the slightly produced apex. The angle 

 between the carinal and scutal margin is also produced, and nearly of the same size as 

 the apical angle. The occludent margin is a little arched, and only a little shorter 

 than the scutal margin. 



The carina has the roof quite flat, and not very much increasing in width from the 

 upper to the lower extremity. The sides are well-developed everywhere, almost of the 

 same width and at right angles to the roof. The roof is considerably bowed. 



The upper latus is irregularly trapeziform. The short carinal margin runs parallel 

 with the longer scutal margin ; the latter, however, is slightly hollowed out. The umbo 

 of the valve is at the apex, which reaches over the scutum, as, though in a less degree, 

 the whole scutal margin does. The angle formed by the scutal and basal margins Ls 

 truncated, hence the valve pentagonal. 



The rostral latus has the umbo at the upper extremity of the rostral margin. This 

 margin is straight and rather long. The scutal margin is hollowed out, the short basal 

 margin forms a rounded angle with the slightly arched lateral margin. 



The infra-median latus is irregular, quadrangular, elongate, narrow. Its umbo is 



