8 



BUIXETIN 36 



354 



10. Pseudoliva vestuta (Conrad). 



1 1 . Ringicula dalli Clark. 



12. Strepsidura subscalarina Heilprin. 



13. Teino stoma Icsvis (Meyer). 



14. Teinostoma subrotunda Meyer ? 



15. Turritella clevelandica Harris, var. Harris. 



SCAPHOPODA 



1. Dentalhi?n minutistriatum Gabb. 



2. Dentalium thalloides Conrad. 



Genus LIRODISCUS Conrad 

 Lirodiscus virginianus n. sp. PI. 1. Fig. 1. 



Description. — Shell thick, subrectangular, umbones flattened; 

 surface ornamented with prominent, concentric undulations ; 

 margin crenulated. 



Long. 19 mm. ; alt. 14 mm. 



This species is of the L. telli?ioides stock but differs from the 

 typical specimens in the lack of the posterior sulcus and from all 

 varying forms of that species in the less rounded, ventral margin, 

 in this respect virginianus is more like L. protractus ? Dall. 

 Meyer's figures of protractus show a greater production of the 

 posterior end, as well as the margin entire. L. smitkvil/ensis 

 Har. is shorter and more rounded. 



From material collected on 1st lanthina Expedition, '97. 



Genus MACTROPSIS Conrad 

 Mactropsis Olssoni n. sp. PI. 1. Figs. 4, 5. 



Description. — Shell moderately thin, triangular ; posterior 

 umbonal slope prominent, angulated, the sharpness of the angu- 

 lation varies in different specimens, on the type specimen the 

 slope is great enough to hide the posterior margin from an ex- 

 ternal, medial view ; beaks high and full ; posterior and anterior 

 regions with large, well-marked areas, differentiated by indenta- 

 tions which extend from the beak to the margin of the shell. 

 Exterior surface with prominent, regular, concentric striae, which 

 decrease in number and become more pronounced on the anterior 

 and posterior, dorsal areas. 



