Vlll NOTES ON THE STENOGYRIN^. 



to Homorus. The African genera seem to be closely related 

 except the insular Bocageia and Chilonopsis, which are spec- 

 ialized groups. Africa is the headquarters of the Subulinoid 

 group. 



Subulina octona has been described and dissected very fully 

 by Wiegmann. The jaw varies from finely and closely striate 

 (pi. 50, fig. 25) to plaited, the latter condition due appar- 

 ently to immaturity. The radula has from 30,1,30 to 36,1,36 

 teeth (pi. 51, fig. 1). The middle tooth has a well-developed 

 cusp with more or less distinct traces of side cusps, especially 

 in embryos, indicating a primitively tricuspid condition. The 

 lateral teeth are tricuspid, and ipass gradually into the mar- 

 ginal type. The latter remain tricuspid, but often the ecto- 

 cone is split on the outer teeth. 



The kidney Is long, triangular, somewhat curved, 6 or 7 

 mm. long, 1.8 wide at the base. It is about half as long as 

 the lung and three or four times the length of the pericar- 

 dium. The secondary ureter is closed throughout. 



The genitalia (pi. 50, fig. 24) are remarkable for the great 

 development of the female organs, with poorly developed or 

 rudimentary male organs. In immature shells of 6 mm. 

 length there are eggs in the uterus, while the penis, etc., is 

 very little developed, suggesting that the female organs pre- 

 cede the male in functional activity. The small penis is 

 simple, as in Rumina, with a terminal retractor. The uterus 

 contains several at most four or five subglobular, hard- 

 shelled eggs 2 to 2.1 mm. in diam., the anterior ones contain- 

 ing embryo shells. The spermatheca has a very short duct. 



The right ocular retractor passes between the branches of 

 the genitalia. 



The dentition of Homorus, Chilonopsis, etc., has been fig- 

 ured in Vol. XVII. 



II. Leptinaria phylum. 



Ovate or turrite shells with the columella truncate at base, 

 and the parietal wall usually armed with a median lamella, 

 though it is often absent. Reproduction oviparous or vivip- 



