X NOTES ON THE STENOGYRIN^. 



indicated. The jaw is like that of Subulina octona. The 

 central tooth is very small and rudimentary, without traces 

 of side-cusps. These are rather weakly developed on the 

 laterals. The -genitalia are figured, pi. 50, fig. 22. The vas 

 deferens is dilated before entering the penis. The penis is 

 rather slender, thickened club-like towards the apex, where 

 the retractor is seated. The very short-stalked spermatheca 

 is inserted on the atrium, below the insertion of the penis, a 

 remarkable position, which was however verified by the ex- 

 amination of more than one specimen. The uterus contained 

 either eggs or embryos in specimen dissected by Strebel, and 

 also in shells I have opened. 



Prosopeas acutissimum has a low arcuate jaw which shows 

 very fine vertical striation under a high power. Radula with 

 about 38,1,38 teeth. The narrow middle tooth has a small 

 cusp. The lateral teeth are tricuspid, with long, slender 

 mesocones. The marginal teeth often split the ectocone (pi. 

 51, fig. 5). The radula of P. tckehelense is similar. 



IY. Rumina phylum. 



This group is somewhat heterogeneous. One genus (Ru- 

 mina) has a bulbous, hemispherical embryonic shell which is 

 lost in the adult, and it is oviparous. The others have a 

 rather conic and entire summit. Zootecus is viviparous. All 

 have the shell opaque, earthy, with the columella bulimoid, 

 or at least not distinctly truncate at base. The following 

 genera are placed here : 



Madagascar. N. Africa, S. Europe, S.-E. Asia. 



Clavator. Riebeckia, Zootecus, Rumina. 



Nothing is known of the soft anatomy or reproduction of 

 Clavator. The dentition of Riebeckia and the anatomy of 

 Rumina have been described in vol. xvii, pp. 205, 211. 



The teeth and jaw of Zootecus have been examined by Mr. 

 A. Protz (Archiv fur Naturgeschichte 1895, p. 106, pi. 8, f. 

 5, 6, insularis, and f. 7, 8, pullus), and by myself. The jaw 

 is arcuate with rounded ends, with very fine vertical striae. 



