137 



In a second type, variety /3, the shells are more rugodens ; 

 scabrous, but thinner. They are usually of small or medium 

 size, and are the most richly colored. A modification of this 

 type sometimes occurs with a more elevated spire. 



In a third type, variety y, the sculpture is more like that 

 of the first, but the outline is more angular, and the shell at- 

 tains a great size. The colors are not as vivid as in variety |S. 



The figure in Sowb. Thes. (pi. I. fig. 17) is more angular, 

 and has a more elevated spire than any of the sliells which I 

 have seen. 



The following: are the dimensions of these varieties : 



Var. a, mean div. 91° : height .53 inch : great, br. .63 in. : least br. .5 i 

 - ^, 1, " 



Fig.inSowb.Thes.80°: 



Cyclostoma sagittiferum. Shell elongate, ovate conic : 

 dingy white, with numerous inequidistant dark brown zigzag 

 lines, with the four angles which are directed backwards ar- 

 ranged in spiral series on stripes of paler brown ; with irregu- 

 lar transverse spots of dark brown next below the suture : 

 with very crowded fine transverse ridges, which interrupt 

 minute spiral elevated lines : apex truncate, with the loss of 

 — whorls : spire rather long, with the outlines curvilinear : 

 whorls remaining after truncation four, quite convex, with a 

 well impressed suture : aperture obliquely ovate, with two 

 peritremes ; of which the outer one is moderately produced 

 and not reflected posteriorly, but in the rest part is well pro- 

 duced, reflected nearly into the plane of the aperture, sinuous 

 on the left side anteriorly ; inner peritreme thick, moderately 

 produced, slightly reflected : umbilicus very narrow, extend- 

 ino: throusfh the truncate summit. 



