THK NAUTILUS. 105 



valves 1-slit; sinus smooth, not toothed; girdle densely, closely 

 clothed with short calcareous spinelets. Type Ch. piceus, of 

 West Indian coasts. This group is Acanthopleura of Cpr., not 

 Guild ing. 



(3) Amphitomura (s. g. nov.) 



Posterior valve having the insertion-plate very short, with blunt, 

 crenulated edge, interrupted only by a single mopaloid slit on each 

 side ; median valves 1-slit ; sinus smooth ; girdle as in s. g. Mmigeria- 

 Type Ch. borbonicus Desh. The tail-valve alone differs from 

 Maugeria, but this character is so significant and so strongly 

 developed that the necessity of separating the two subgenera is 

 obvious. 



(4) Mesotomura (u. nov.) 



Posterior valve having the long insertion plate deeply pectinated 

 outside, its edge interrupted only by a single median-posterior slit; 

 median valves 1-slit; sinus denticulate; girdle sparsely set with 

 spike-like spines. Type C. echinatum Barnes. Corephium Gray, 

 1847, not Browne, 1827, is a synonym. 



Mention should be made of the curious fact that Gould's Ch. 

 incanus and the similar Japanese species C. /aponictts Lischke, have 

 been by all authors referred to Acanthopleura. An examination 

 shows them to differ wholly in the characters of the tail-valve, the 

 incanus, etc., having a smooth crescentic callus in place of the 

 insertion-teeth. It therefore belongs in the immediate vicinity of 

 Onithochiton, from which it differs in the spiny girdle and rough 

 exterior. The group may be called Liolophura, Ch. japonicus 

 being the type. 



A NEW TROCHID FROM JAPAN. 



BY H. A. PILSBRY. 



Calliostoma Crumpii, n. sp. (pi. I, fig. 3.) 



Shell closely resembling C. argenteo'idtens Lischke (Manual of 

 Conchology xi, pi. 6-3, fig. 32) in contour, color and texture. Differ- 

 ing from that species in the more convex whorls of the spire, the 

 deeply channelled suture, and in sculpture. The body-whorl is 

 rounded, and has a girdle of prominent tubercles at the periphery ; 



