282 PROCEEDINGS OF THE ACADEMY OF [Feb., 



to be perceived. Spiniger is confined to the Upper Vicksbiirg marl, 

 while nodulatum has occurred thus far only in the Lower Mcksburg 

 limestone. The latter differs in both form and sculpture from 

 spiniger, but varies of course in the relative amount of shoulder exposed 

 above the suture, as is generally the case throughout the genus. The 

 form occurring at Red Bluff differs from spiniger in its larger size, 

 rather more elongated form, feebler sculpture, less strongly diffoi-en- 

 tiated whorls of the spire, and more feebly developed spines of the spire 

 whorls, also in usually having traces of a fine subobsolete, remotely and 

 minutely subnodulose line at some distance below the spinose shoulder 

 line. It may not be more than a subspecies of spiniger, but resembles 

 that species more closely than nodulatum, from the intermediate beds 

 constituting the Lower Vicksburg, a case very similar to that before 

 referred to under Mactra. 



Lyria nestor n. sub-sp. 



The Lyria misssisippiensis, of Conrad, moderately abundant in 

 the Upper Vicksburg marl, is represented in the Red Bluff bed b)^ 

 this form which must be regarded as at least subspecifically distinct. 

 It is much more elongate in outline than the Vicksburg species, and 

 is more distinctly sculptured. The longitudinal ribbing is more 

 obtusely rounded and less distinct. The length of a moderately large 

 specimen is about 43 mm., with a maximum width of 18 mm. It is 

 accurately figured by Dall (Trans. Wag. Inst., Ill, PI. 6) under the 

 name Lyria costata Sowerby, and, in his opinion, both this and the 

 Vicksburg form are varieties of that European species. The Vicks- 

 burg and Red Bluff forms are, however, distinctly differentiated in 

 facies and each holds to its own type through very extended series, 

 without exhibiting much variability. 



Conrad's type of Conomitra staminca is apparently unique as far as 

 the Vicksburg strata are concerned, and, from the matrix that partially 

 envelops it, would appear to have come from the upper marl. It is 

 a small species, about the size of the Claibornean fusoides and somewhat 

 of the same form. The revolving grooves are deep and do not cross 

 the ribs, thus forming short and very conspicuous excavated hues, 

 nearly a^s in Fusimitra cellulifera Conrad. The species figured by Dr. 

 Dall (I.e., PL 4, fig. 2) is quite evidently distinct from siaminea, and 

 is a much larger species. It also seems to be distinct from angulata 

 Heilp. The specimen figured by Dr. Dall has five body whorls and 

 measures 15 mm. in length. A specimen of the true staminea, 

 recently lent me by Mr. Aldrich and found at Byram's Ferry, having 



