NO. 1908. NEW 8ILURTAN MOLLUSCA FROM MAI\E—WILLIAM><. 395 



STREPTOTROCHTJS lONE, new species. 

 Plate 50, fig. 13. 



Shell small, thin, whorls six, including the initial protoconch, angle 

 of spire about 45 degrees. The second, third, and fourth (counting 

 the protoconch as one), are simply rounded ; the fifth is rather sharply 

 carinated about halfway between the sutures; the sLxth and last 

 wliorl is (on the right side of the figure) at first rounded without 

 carinatiou, but toward the mouth becomes indented by a furrow 

 corresponding to the posterior face of the preceding wliorl. The sur- 

 face is covered by concentric lines and occasionally more prominent 

 ridges, irregular in size and in direction, but having the appearance of 

 having formed the outer margin of the lip at successive stages of 

 growth. 



Locality. — On the west side of Shackford Head, Moose Island, East- 

 port, Maine. 



Holotype.—Ceit. No. 58447, U.S.N.M. 



STREPTOTROCHUS REGULARIS, new species. 



Plate 50, fig. 12. 



This specimen is apparently made up of four whorls; the tip is 

 broken. All of the whorls are convex and not carinated, but upon 

 good exposure the whorls are seen to have a faint blunt angulation, 

 and the outer whorl shows faintly the indentation more distinctly seen 

 in the species Streptotrochus ione. The angle formed by the sides of 

 the spire is approximately the same as in Streptotrochus ione. The 

 surface markings consist of both the fine lines and the irregular larger 

 concentric foldings which follow the direction of the edge of the lip. 



Locality. — Same as Streptotrochus ione. 



Holotype. —Cat. No. 58446, U.S.N.M. 



STREPTOTROCHUS CARINATUS, new species. 

 Plate 50, fig. 8. 



This specimen is more slender than Streptotrochus ione, the sides 

 forming an angle of about 35 degrees. The smaller and initial whorl 

 is absent, but from analogy there were probably six original whorls. 

 The last three whorls are each distinctly carinated and the carination 

 is near the outer side and suture of each whorl; the -wider or right-hand 

 side of the whorl is flattened and hollowed immediately below the 

 carination, forming thus a broad shallow groove. This specimen is 

 exfoHated and the characters are based upon the surface of the anterior 

 mold. Other specimens, however, preserving tlie shell show the shell 

 to have been very thin, and except for surface markings the interior 

 molds show the form of the exterior surface. 



Locality. — Same as Streptotrochus ione. 



Eolotype.—C&t. No. 58444, U.S.N.M. 



