258 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.59. 



icus nor to touch the whorl above. Above the aperture the outer 

 peritreme is expanded to form a delta-shaped projection and ending 

 in a siphon which bends back and sometimes downward into the 

 space between the solute last whorl and the whorl above. The 

 operculum is typical of the genus. 



This species includes two subspecies as follows: 



OPISTHOSIPHON (OPISTHOSIPHONA) EVANIDUM EVANIDUM, new subspecies. 



Plate 41, figs. 1-2. 



This, the typical subspecies, is distinguishable chiefly by its uni- 

 formly greater size and by its whiter coloration. 



Type.— Cat;. No. 314955, U.S.N.M., is from the estate of "La 

 Loma '• near El Tuabaguey in the eastern part of the Cubitas Moun- 

 tains, in the Province of Camaguey, and was collected by Pablo Si- 

 fontes, jr. It measures: Length, 13 mm. ; greater diameter, 8.5 mm. ; 

 lesser diameter, 6.75.; length of aperture within, 4 mm.; width of 

 aperture within, 3 mm. 



OPISTHOSIPHON (OPISTHOSIPHONA) EVANIDUM DEGENERATUM, new subspecies. 



Plate 41, figs. 3 and 8. 



This subspecies is characterized only by its persistently smaller 

 size, but in all other respects it could hardly be separated from the 

 typical subspecies. The spiral cords within the umbilicus are 

 reduced to the minimum, in some specimens being scarcely 

 observable. 



Type.— Cat. No. 314956, U.S.N.M., was collected by Torre and P. 

 Sifontes, Sr., at Santa Cruz, a detached hill, on the right bank of the 

 river Maximus opposite u Los Cangilones" in the Province of Cama- 

 guey, Cuba. It measures: Length, 11. mm.; greater diameter, 

 7.25 mm.; lesser diameter, 5.75 mm.; length of aperture within, 3.75 

 mm.; width of aperture within, 3 mm. 



OPISTHOSIPHON (OPISTHOSIPHONA) OCCULTUM, new species. 



Plate 41, figs. 4, 6, and 7. 



The shell is ovate-conic, spire decollated, leaving three and a half 

 to four moderately convex whorls, the last very slightly solute, the 

 umbilicus being almost wholly covered by an expansion of the 

 peristome. The color ranges from a light straw to a light amber 

 and is always ornamented by encircling rows of elongated chestnut 

 spots which appear upon the reflected portion of the peristome. 

 These spots are often so exposed as to give an appearance of axial 

 rows as well as spiral; in no instances are there solid color bands. 

 The sculpture consists of axial riblets, more widely spaced upon the 

 early postnuclear whorls and more crowded upon the last whorl, 

 where there are five to six to a millimeter. Many of these axial 



