NOTES ON THE STENOGYRIN^E. ix 



arous. Radula of the ordinary Stenogyroid type. This 

 group has characters of both the Subulina and the Opeas 

 phyla. The genera are Leptinaria (p. 284) and Ochroderma 



(p. 325). 



III. Opeas phylum. 



Chiefly small, thin, ovate or turrite snails, usually per- 

 forate or rimate, with the columellar margin dilated, straight 

 or concave, passing without truncation or notch into the 

 basal margin. No parietal lamella. Oviparous or viviparous. 

 Dentition as in Subulina,, etc. The genera follow: 



America. Africa. 8. E. Asia, etc. 



Hypolysia. 



Curvella. Curvella. 



Opeas. Tristania. Opeas. Opeas. 



Pseudopeas. Pseudopeas. Eremopeas. 



Prosopeas. 

 Plicaxis. 



Perrieria. 



This phylum contains the <most widely-spread groups, such 

 as Opeas, which extends into Polynesia and has been found 

 in German miocene deposits, and Pseudopeas, which is repre- 

 sented in South America and Africa, and in the subgenus 

 Eremopeas extends into Australia, the only indigenous mem- 

 ber of the Achatinidce in that continent. Except Curvella, 

 the other genera are restricted to comparatively small areas. 

 Nothing is known of the soft anatomy of most of the genera. 



Opeas panayensis (pi. 50, fig. 23, after Semper) has a 

 larger spermatheca duct than Subulina octona. An egg 

 dilates the uterus in the preparation figured. The kidney is 

 very short. The same species was found by Wiegmann to 

 have 28,1,28 teeth (pi. 51, fig. 2) . There is a minute side- 

 cusp on each side of the mesocone of the middle tooth. The 

 laterals are nearly symmetrical, tricuspid. 



Opeas caraccasense (= beckianum) from Misantla, V. C., 

 Mexico, has been examined by Strebel. The foot (pi. 50, fig. 

 22) is short, with coarse rugae, the marginal zone distinctly 



