35 



carina."* The brief and rather vague description of Bucania angustata, 

 by the same author, is as follows : "Volutions narrow, rounded on their 

 sides, expanding near the apertm-e. The specimen figured is a rough 

 cast in limestone, preserving no remains of sui-face markings. The 

 volutions are less extended laterally than any other species of equal 

 size known in our 8trata."f 



Most of the specimens of T. Alpheus in the Museum of the Survey 

 are, however, very strongly compressed at the periphery, and these 

 agree perfectly in shape with Hall's figui-es and description of Bucania 

 angustata. The "interrupted oblong nodes" on the periphery, which 

 seem to be always present in casts of the adult shell of T. Alpheus, are 

 said to be absent in B. angustata; but this statement may very well 

 have been due to the accidental circumstance that the type and only 

 specimen known of the latter species happens to be too imperfectly 

 preserved to show them. 



On page 304 of the second edition of the " American Palseozoic 

 Fossils," Ml-. S. A. Miller says that T. Alpheus is a synonym for Bucania 

 Ohicagoensis. 



EOCULIOMPHALUS CIRCINATUS. (N. Sp.) 

 Plate 5, figs. 4, 4a, 4b, and 4c, and pi. 8, fig. 5. 



Shell sinistral, composed of about one and a half free and discon- 

 nected spiral volutions, which are coiled nearly on the same plane and 

 which increase rather rapidly in their dorso-ventral but more slowly in 

 their lateral diameter ; upper side somewhat flattened vertically or 

 gently convex ; periphery subangulated or narrowly rounded ; under 

 side rather strongly convex, subcarinated or more or less faintly sub- 

 angulated in the middle, especially near the mouth ; aperture ovately- 

 triangular, inequilateral, unsymmetrical and higher than wide. Surface 

 of the test densely striated across ; upper side of the outer half of the 

 last volution of the cast marked by two distant and nearly parallel 

 spiral gi'ooves, one of which is placed near the inner edge and the other 

 about the middle. Posterioi- extremity, in one specimen at least, dis- 

 tinctly septate or chambered, the septa being simple, concave, and 

 placed at distances of from one to two millimetres apart. 



Gait, Eev. Andrew Bell, 1846-50 : Gait and Hespeler, T. 0. Weston, 

 1867 : Elora, D. Boyle : Durham, Mr. J. Townsend. 



* Eighteenth Eeg. Rep., p. 347. 

 t Idem. 



