dall] 



NOTES OX SOME UPPER CRETACEOUS VOLUTID.E 



21 



the external spiral cords, and not on the true plaits ; early whorls 

 with 8-10 rounded axial riblets, obsolete on the last whorl; suture 

 appressed, the whorl in front of it flattish, with no well-marked 

 shoulder, but more or less distinct axial wrinkling just in front of 

 the suture; on the last whorl there are 15-17 prominent, distant, 

 sharp spiral ridges, without nodulations ; sepa- 

 rated by much wider, slightly excavated, ax- 

 ially striate interspaces in which occasional 

 much finer intercalary spirals sometimes ap- 

 pear; outer lip thin, in the adult anteriorly 

 expanded, slightly reflected ; the posterior sinus 

 narrow, well marked, close to the suture. Lon. 

 124; of aperture, 87; max. diam. 33 mm. 



VOLUTODERMA PROTRACTA Dall, n. sp. 



(Figure 10) 



Shell very elongate, thin, with 8 whorls ; pillar 

 straight, with three feeble plaits lagging be- 

 hind the aperture ; on the early whorls 7-8 

 rounded axial ribs, obsolete on the later 

 whorls ; whorls slightly constricted in front of 

 the appressed suture ; sutural margin with con- 

 spicuous imbricated scales and striation axially 

 directed, crossed by 3-5 faint spiral threads ; 

 on the body of the last whorl are 19-20 sharp 

 spiral ridges with much wider, somewhat ex- 

 cavated interspaces ; the spiral ridges are some- 

 times gently undulated but not nodulous, and 

 there are occasionally faint intercalary spiral 

 threads ; outer lip thin, slightly reflected ; pos- 

 terior sinus close to the edge of the suture. 

 Lon. 155; of spire above the first whorl, about 

 40 ; max. diam. 36 mm. 



Types are from the Ripley formation at Eu- 

 faula, Alabama, U. S. Nat. Mus., No. 21,129; 

 other specimens are from the same horizon at Owl Creek blurt", Rip- 

 ley, Miss. (20,430) ; and Kaufman, Texas (20,992). 



The figure given of this remarkable species is diagrammatic, being 

 a restoration from a number of fragmentary specimens. The shell 

 is so thin that no specimen was collected showing an entire shell of 

 adult stature. The specimen from Texas is partially an internal 



Fig. \o.— V. pro- 

 tracta Dall. %. Pos- 

 terior sinus shown in 

 profile. 



