+2 THE VOYAGE OE B.M.S. CHALLENGER. 



Observations. — This species is one of those which were collected at Stations situated 

 far from one another. Whereas one Station is in the Atlantic, nearthe Azores, the other 

 is in the Pacific, near the Kermadec Islands. 



b. Without a sub-carina. 

 (a.) Species with a rostrum. 



Scalpellum brevecarinatum, n. sp. (PL III. fig. 22). 



Valves fourteen, covered by a very thin membrane only. Carina very short, simply 

 bowed, with the umbo at the apex. Upper latus quadrangular. Valves of the lower 

 whorl, and especially the carinal latera, large. Rostrum wedge-shaped. 



Of this curious little deep-sea species two large and three very small and young 

 specimens were collected. They agree with Scalpellum balanoidss in the shortness of 

 the carina. 



The capitulum is flat, and consists of fourteen valves covered by a very thin chitinous 

 membrane ; in consequence of this the white colour of the valves has become slightly 

 yellowish. The high development of the valves of the lower whorl is especially charac- 

 teristic of this species. 



The scutum is trapeziform ; about twice as long as broad. The apex is slightly 

 recurved, and projects over the tergum as a small triangular part. The occludent margin 

 is arched, the lateral margin also ; the tergal margin behind the projecting triangular 

 part is straight. 



The tergum is triangular ; its occludent margin arched ; the apex is recurved, the 

 carinal margin slightly arched, the scutal margin almost straight. It surpasses the 

 scutum in area. 



The carina is short, simply bowed.' The umbo is at the apex. The roof is not quite 

 flat, and slightly furrowed longitudinally. In the uppermost portion small parts which 

 must be considered as sides are visible. 



The rostrum is elongate, narrow. The umbo is at the upper extremity, which is 

 slightly narrower than the base. 



The rostral latus is trapeziform. The scutal margin is much longer than the basal 

 margin. The latter is straight, the former slightly hollowed out. 



The infra-median latus has about the same shape as the rostrum. It is slightly 

 protuberant over the surface of the other latera, Its umbo is at the upper extremity. 



The carinal latus is very large and of an elongate pentagonal 'shape. The lateral 

 margin is long and straight, the basal margin is rather short ; the carinal margin is divided 

 into a superior portion which is hollowed out, and into a rather long and slightly convex 



