1921] NATURAL SCIENCES OF PHILADELPHIA. 343 



rounded axial folds, weak below the suture, 6 or 7 on a whorl, and 

 fine axial costulation, over which about 8 rather acute, narrow 

 spiral threads run. On the last 2 or 3 whorls the axial folds are 

 replaced by small, rounded tubercles disposed along a slight shoul- 

 der angle; the spirals become weak and sparse except towards the 

 base. The suture is rather narrowly, deeply channelled. At rest- 

 ing stages and the final lip the suture rises very little. There are 

 three strong plaits, the anterior one lowest and thickest. The largest 

 shell measures 176 mm. long, 80 wide. This species differs from 

 X. rex "in its tubercles, which are small and rounded, "and the less 

 emphatic sculpture generally. 



X. validuff differs from Turhinella ovoidea Kiener l)y the channelled 

 suture and the more prominent axial folds of the spire. T. regina 

 Heilpr. is more elongate than X. validus at all stages of growth. 

 T. scolymoides Dall has more elaborate sculpture, the axial folds 

 persisting longer, and the columellar plaits are smaller. T. ivilsoni 

 Conr. is more shouldered, with larger nodes. T. polygonata Heilpr. 

 seems to resemble T. wilsoivi rather closely, but no good adult speci- 

 mens have been found. 



Fasciolaria textilis Guppyi'* is less excavated below the periphery 

 than the present species, but a form of the Bowden bed which we 

 had provisionally called Xancus texlUisjamaicensis (PI XXV, figs. 5, 6) 

 is rather closely related. It has conspicuous axial wrinkles above 

 the shoulder, which is more developed and has larger nodes than 

 X. validus. The first whorl following the embryonic stage has 

 about twice as many axial folds as the succeeding whorls, and the 

 suture is not in the least channelled. 



A variety of X. validus with somewhat larger nodes at the shoul- 

 der was taken by Mr. L. B. Smith west of Azua, Haiti.. 



Xancus praeovoideus Mamy. 



Turbindla ovoidea Gabb, Trans. Amer. Philos. Soc. xv, p. 218; not T. ovoidea 



Kiener, 1840. 

 Xancus procevoideus Maury, Bull. Amer. Pal. v, p. 83. 

 Xancus prceovoideus Maury, op. cit. p. 241. 



This fine shell, which Gabb collected in considerable quantity, 

 differs from the recent X. ovoideus by the strong sculpture of the 

 neanic whorls, as Miss Maury has pointed out. It reaches a length 

 of 175 to about 200 mm. The suture usually rises abruptly at rest- 

 ing stages and behind the final peristome. 



It differs from X. validus by the smoother later whorls. In a 



» Geol. Mag. 1874, p. 140, pi. 16, fig. 5. 



