126 K. J. Bush — Marine Gastropods referred to 



Circulus Smithi Bush. 

 Cyclostrema tricarinatus Smith, P. Z. S., London, p. 737, pi. 75, fig. 26, 1871. 



In studying the various figures published in Tryon's Manual I was 

 impressed with the strong resemblance of the African species, Cy- 

 clostrema tricarinatus Smith, to the Crag species of Adeorhis Wood, 

 esp. tricarinatus. I referred the matter to Mr, Smith, who writes 

 me that upon comparing his species with those of Wood, he finds 

 that there is unquestionably no generic distinction. He also states 

 that his figures are accurate representations of the only specimen 

 which he had of his species. As the specific name tricarinatus is 

 preoccupied by Wood, I propose the name Smithi for this African 

 shell. It differs from any of those on our coast which belong to 

 Circulus, in having the entire surface covered by conspicuous revolv- 

 ing threads and grooves, in addition to three prominent cai'infe. 



Circulus Dalli sp. nov. 

 Plate XXIII. figs. 3, 3« and 6. 



A single dead specimen, found among foraminifera, at station 2655, 

 N. lat. 27" 22', W. long. 78° 07' 30", in 338 fathoms, 1886. 



This deep-water species is of more delicate texture and more trans- 

 parent than the more northern shallow-water species of similar form. 

 It is ornamented on the body-whoi-1 with two rather inconspicuous 

 carinae, one defining the base and the other on the periphery; above 

 this the surface is cut by about seven delicate, unequal, microscopic 

 shallow grooves or strise, the two uppermost being the most distinct; 

 above these the surface is smooth and appears somewhat flattened ; 

 there are also a few less distinct striae below the periphery and in 

 the umbilical region. 



Greatest width, about 3°^™; height, about 1-4'°'". 



A smaller dead specimen (No. 44983) from station 2307, off Cape 

 Hatteras, N. C, in 43 fathoms, agrees well with this species. It has 

 however, in addition to the typical sculpture, a few smaller striae 

 just below the suture, and the grooves and alternating raised lines 

 appear more distinct, the specimen being very much worn and twice 

 injured and repaired by the animal. 



This larger species, in its inconspicuous sculpture, seems to be a 

 connecting link between the distinctly grooved ones and the cari- 

 nated ones, so that we have a series of gradations in sculpture from 

 the smooth variety of supranitidus thi'ough supranitidus (typical), 

 trilix, Dalli, Smithi, striatus, up to the strongly grooved liratus. 



