I 2< I 



the peduncle are very distinct, al .ome distance from one another and 

 [itudinal rows. The length of the peduncle is about half the length of the capitulum. 

 total length of the animal is 7,8 mm., that of the capitulum 5,5 mm. 

 took the specimen at 



Lal ; \.. I ! E. Depth 204 m. Bottom: hard 



il s. nul. 



/////// 11. sp. PI. IX, fig. 4. 



\ .'..- thirteen covered with ;i delicate brownish membrane. Carina with the umbo at 

 the apex and with a flat roof bordered by ridges. Lateral margin of the scutum with a deep 



ir incision near the upper extremity for the reception <>i 1 1 1 « - apex <>t the upper latus. 

 Valves "f tin- lower whorl large. Infra-median latus wine-glass shaped with the umbo near the 

 Carinal latus quadrilateral with the umbo near the base. 



This curious di cies is represented liy a single specimen only. 



The capitulum is rather flat, little more than twice as long as broad, having the 

 carinal margin slightly mort- convex than the occludent margin. The apex of the tergum is 

 pointed and a little recurved. TIn- surface is of a browny yellowish colour; scratching it with 

 a needie a very delicate skin or membrane loosens in little flocks from the surface. The ridges 

 «>f growth are very distinct on most of the valves; parallel furrows are visible <>n the scutum, 

 on tin- upper latus and also on the carinal latus near the- base. The valves are separated from 

 each other l>v narrow, hut distinct chitinous interspaces; that between the tergum and tin- upper 

 halt" of th<- carina being much broader than tin- others. 



The scutum has a very characteristic shape. lts occludent margin is convex; its tergal 

 margin hollowed out near the apex and convex towards the other extremity. The lateral and 

 basal margins slope into one another quite insensibly; near the upper extremity the lateral 

 margin shows a very characteristic incision in which the apex oi the upper latus hts exactly. 



The tergum is triangular. lts occludent margin is convex, its carinal margin slightly 

 hollowed out in the upper, slightly convex in the lower part. The apex is not strongly, yet 

 distinctly recurved. 



The carina has a tlat roof which is bordered by ridges, but does not increase in width 

 very strongly from the apex downwards. The sides of the carina are well-developed over its 

 whole length. they increase only slightly in width from the base to the tij» of the valve. 



The upper latus is pentagonal with the sides of very unequal length. The carinal 

 and the basal margin along the infra-median latus are the shortest, the convex tergal margin 

 which is slightly hollowed out in the middle is the longest. The lateral margin is hollowed out 

 and a little longer than the basal margin separating this valve from the carinal latus. The umbo 

 is at the apex which may be called beaked. 



The rostral latus is quadrilateral; the upper and basal margins are of about equal 

 th. the rostral margin is slightly convex, the lateral margin distinctly convex. 



The infra-median latus has the shape of a wine-glass and is relatively large. Both 



120 



