96 TILE VOYAGE OF H.M.S. CHALLENGER. 



upper to the lower extremity. The sides of the carina are at more than right angles with 

 the roof; they increase much in width from the lower to the upper extremity. 



The upper latus is quadrangular, with the lower angle truncated, hence pentagonal. 

 The umbo is at the apex, which is slightly prominent. The scutal margin is hollowed 

 out, the tergal margin slightly arched. 



The rostral latus is of considerable size, quadrangular. Scutal and basal margins nearly 

 parallel ; the whole valve is distinctly convex and divided into two triangular parts by a 

 not very prominent ridge running from the umbo to the basal lateral angle. 



The infra-median latus is small, triangular. The umbo is at the slightly protuberant 

 apex. 



The carinal latus has an irregular shape, resembling that of a shoe. The umbo is at 

 the carinal basal angle and represents the heel of the shoe. The carinal margin (the 

 sole of the shoe) is slightly hollowed out. The upper margin is straight, the lateral 

 margin is very short, the basal margin straight, only slightly upturned towards the umbo. 



Length of the capitulum, 20 mm. 



The peduncle is short (5 "5 mm.), cylindrical, much narrower than the base of the 

 capitulum. 



The scales are covered by membrane, very narrow, transverse, calcareous stripes only 

 being visible. They are not numerous, and do not form very distinct rows ; they are at 

 considerable distances from one another. 



This species was taken at Station 153, February 14, 1874 ; lat. 65° 42' S., long. 79° 

 49' E. ; depth, 1675 fathoms ; bottom, mud. 



Observations. — This species may be easily distinguished from the nearly related 

 Scalpellum velutinum, Scalpellum pedunculatum, &c, by the form of the carinal latus. 

 Though this valve also may perhaps present variations within the limits of a species, in 

 the present case it can be safely made use of. 



Scalpcll unt velutinum, n. sp. (PL IV. figs. 10, 11 ; PL IX. figs. 7-9). 



Surface of the capitulum and of the peduncle covered by a velvet-like membrane. 

 Valves fourteen, the rostrum, however, not visible at the surface. Carina simply and 

 very strongly bowed, with the umbo at the apex, with a flat roof, the apex of which 

 penetrates between the two terga. Upper latus triangular. 



This beautiful species is represented by a single specimen. Provisionally there must 

 lie referred to the same species three smaller specimens, which were dredged near the 

 southern point of Portugal ; yet I am not quite sure that they belong really to the same 

 species. This species is nearly related to Scalpellum regium, Scalpellum darwinii, 

 Scalpellum gigas, Scalpellum robustum, &c, which form together a very natural group. 



