118 THK VOYAGE OF H.M.S. CHALLENGER. 



this and in other cases where the object is small and only a single specimen is present, 

 the fear of spoiling the specimen made me unwilling to dissect it. 



This species occurred at -.Station 1(50, March 13, 1874; Lit. 42° 42' S., long. 134° 10' E. ; 

 depth, 2(300 fathoms; bottom temperature, 0° - 2 C. ; bottom, red clay. 



Observations. — This species shows much resemblance to Scalpellum clistinctum, 

 dredged from a depth of 1070 fathoms in the Pacific Ocean north of New Guinea. The 

 dillcivnt shape of the valves of the lower whorl, and also of the scutum, has made me 

 consider them as different species. The difference in depth is also considerable, but this 

 alone would by no means be of sufficient importance to separate the species. 



Scalpellum australicum, n. sp. (PI. V. fig. 11). 



Surface of the valves naked, with slightly prominent ridges. Valves thirteen, closely 

 locked together. Carina with the umbo at the apex, simply bowed, with the roof flat 

 and bordered on each side by a rather prominent ridge. Upper latus trapeziform. Infra- 

 median latus narrow, elongate. Umbo of the carina! latus projecting beyond the carina. 



Of this species only a single specimen was collected ; from the same locality a 

 specimen of Scalpellum dubium, and one of Scalpellum truncatum were obtained. 



Capitulum flat, consisting of thirteen valves. Valves naked, with distinct ridges 

 and furrows. There are no distinct interspaces between the different valves. The shape 

 of the capitulum is elongate-oval. 



Scutum slightly convex, with the occludent margin arched ; the tergal margin is 

 feebly undulating, being hollowed out near the apex ' and convex towards the lateral 

 margin. The umbo is at the apex, which projects over the tergum ; the lateral margin 

 is very irregular, the umbo of the upper latus projecting a great deal over the scutum. 

 The basal margin is rather short, straight, and at an angle less than 90° with the 

 occludent margin. 



Tergum triangular, with the occludent margin arched, the carina! margin undulating, 

 and the scutal margin rather irregular. The umbo is at the apex, which is distinctly 

 recurved. 



Carina simply bowed, with the roof flat and bordered by distinct ridges ; sides at about 

 right angles with the roof, and much broader near the upper extremity of the valve. 



Upper latus trapeziform, with the apex, where the umbo is seated, projecting 

 very much over the scutum. Carinal margin short, scutal margin hollowed out, basal- 

 scutal angle truncated. 



Rostral latus irregularly quadrangular. Lateral margin straight and rather long, 

 scutal margin hollowed out, basal margin short. The umbo is at the rostral upper 

 angle of the valve, and projects over the occludent margin ; from the umbo a curved 



