ORCULA. 41 



bristle stands at the upper third, so that the crown of hairs 

 stands near the suture, and not, as in 0. doliolum, at the lower 

 edge of the whorls. Reinhardt (1880) made the same obser- 

 vation on specimens from the Caucasus, which show somewhat 

 whitish epidermal riblets which are rather distant on the 

 upper whorls, and produced in a rather long hair-like spine 

 on the upper part. The last whorl may have even two rows 

 of spines. In most specimens in collections these spines are 

 very slightly developed or are entirely rubbed off. 



Internal structure (pi. 4, figs. 2, 5). — The parietal lamella 

 becomes a little lower as it enters. Within the left side it 

 begins to enlarge, and the edge flares outward. On the ven- 

 tral side it attains maximum size, and on the right side the 

 flare disappears and the lamella diminishes rapidly; its total 

 length is about li/o whorls. The columellar lamella becomes 

 very wide within, nearly meeting the enlarged parietal lamella 

 on the ventral side ; after that diminishing to the size of the 

 supracolumellar lamella, which is nowhere enlarged. The 

 infracolumellar lamella is short, near the aperture only. 

 Specimens from Suran measure : 



Length 4.5, diam. 2 mm. ; 9 whorls. Fig. 4. 



Length 3.8, diam. 2 mm. ; 8 whorls. Fig. 6. 



Form quadrifilaris Rosen. PI. 4, fig. 7. Having a fourth 

 columellar fold below the three characteristic of trifilaris. 

 The most conspicuous difference making it easily known from 

 all the other forms is the quite flat summit of the shell, which 

 appears as though truncate. The shell of 4.2 mm. long has 

 7y 2 whorls, of which the first 3% form a flat surface with 

 scarcely projecting apex. Drift of the Psekup, Caucasus; 

 2 found among 14 bifilaris (Rosen), 



In his paper of 1911 Rosen states that he has recently 

 found equally truncate bifilaris Mouss., and Dr. "Wagner in- 

 formed him that in typical raymondi of Asia Minor the trun- 

 cate spire also occurs. He has named the form bifilaris trun- 

 cata, and figured a specimen from flotsam of the Psekup (see 

 pi. 4, fig. 8). Rosen also figures what he calls P. raymondi f. 

 quadrifilaris truncata, copied in our pi. 4, fig. 7. This is 

 exactly what he formerly called quadrifilaris, from the same 

 place. 



