324 PROCEEDINGS OF THE ACADEMY OF [PaRT II 



and widely spaced in the peripheral region and above. Between 

 them are many minute spirals and rather sharp axial striae (Plate 

 XVI, fig. 11). 



Length 28.5, diam. 7.5 mm., aperture 12.5 mm. long; 10 whorls 

 (not 11 as stated by Gabb). 



The type is no. 2914 A. N. S. P. 



Clathurella arnica Pils. and Johns. Plate XVII, fig. 13. 

 Proc. A. N. S. Phila., 1917, p. 158. 



Glyphostoma dentiferum (Gabb) Plate XVII, flg. 15. 



Glyphosloma dcntifera Gabb, Proc. A., N. Sci. 1872, p. 971 [=271], pi. 11 



fig. 4. (Feb. 11, 1873). Tr. Am. Philos. Soc. xv, 1873, p. 210. 

 Clathurella (Glyphostoma) denlifera (Hinds), Cossmann, Journ. de Conchyl. 

 xi, 1913, p. 31, pi. 2, figs. 15-17, with var. martinicensis Cossm., figs 18-20. 



Gabb's figure is not very good. The whorls of the spire have 

 stout, short ribs or npdes at the periphery. On the penult whorl 

 they become smaller and bifurcate below the shoulder, and the 

 last whorl has numerous narrow ribs, part of them uniting by pairs 

 at the shoulder. In the series of 9 individuals, there is very great 

 variation in size and shape. It is possible that with further large 

 series, an assortment into several species would be practicable, 

 though this seems unlikely. The smallest one having a complete 

 adult aperture is 14.5 mm. long, of 9 whorls. Others measure: 



Length 32.4, diam. 13 mm.; 9| whorls (type). 



Length 31 (estimated), diam. 10 mm. 



Length 26.4, diam. 10 mm.; 10| whorls. 



This is type of the genus Glyphostonia. It is certainly distinct 

 from the recent Clavatula dentifera Hinds, but if that species is a 

 Glyphostoma, as seems likely, the name dentiferum Gabb will have 

 to be changed. Perhaps martinicensis Cossmann will be available; 

 but the figures are imperfect and I am not sure that the forms are 

 specifically identical. 



Clavatula labiata Gabb. Plate XVII, figs. 11, 12. 



Clavatula labiata Gabb, Trans. Amer. Phil. Soc. xv. 1873, p. 209. Guppy, 

 Quart. Journ. Geol. Soc. 1876, p. 527, pi. 28, fig. 3. 



This species has a mamillar embryonic shell of If whorls, the 

 first rounded and very bulbous, though small, the last third of the 

 last embryonic whorl becoming angular in the middle. After that 

 the neanic sculpture appears abruptly, strong, protractive peripheral 

 nodes crossed by fine, sharp, spiral threads. On the last whorl the 

 spirals are hardly noticeable except near the base. The crenula- 

 tions within the outer lip are short and sharp. 



