A NEW PERMO-CARBONIFEROTJS GENUS — ETHERIDGE. 199 



Keeneia platyschismoides, sp. nov. 



(Plate xxxii. ; Plate xxxiii., figs. 3 - 5). 



Sp. Char. — Shell very large, massive, turbinate, and the base 

 to some extent flattened. Spire short, of five or six whorls, the 

 apical whorls depressed, and displaying a great discrepancy in size 

 as compared with the penultimate and body-whorl ; sutures close 

 and nonchanneled. Body and penultimate whorls with gently 

 convex surfaces, or the latter at times inclined to become rather 

 straight-walled, shoulder-like around the sutures, where the whorl 

 surfaces are either flat, or slope somewhat inwards ; periphery of 

 the body-whorl obtusely-carinate. Band broad and flat, occupy- 

 ing the obtuse keel, and defined by two or more circumferential 

 impressed lines. Mouth very large and obliquely quadrangular, 

 transversely elongated ; outer lip thickened in the region of the 

 sinus, and judging by the lines of growth, the sinus was wide but not 

 deep or slit-like ; inner lip thickened. Umbilicus subinfundibuli- 

 form. Sculpture of rather coarse growth stripe directed obliquely 

 backwards on the upper portion of the body-whorl, forming a 

 sharp bend in the same direction at the band, resuming their 

 course on the base in a faint sigmoidal curve forwards, and 

 gathered in a puckered manner around the umbilicus, laminar 

 and very pronounced contiguous to the outer lip, no cancella- 

 tion ; on the band, whether exposed or concealed, the striaj are 

 strongly concave backwards. Height, 4"; breadth (across mouth), 

 4|-"- breadth (fore and aft) 4|." 



Ohs. — The relation of this shell to Platyschisma oculus proper 

 has already been described, and need not be referred to further. 

 Dana's illustration, however, of the latter^ has every appearance 

 of being a peculiarly drawn example of Keeneia platyschismoides. 

 Previous to making the acquaintance of this fine Mollusc in its 

 mature state, 1 had seen a young example that I mistook for an 

 exceptionally well preserved and young individual of P. oculus,^ 

 but on receipt of the specimens now under description, the mistake 

 I had made became manifest. In this young condition, not only 

 the backwardly directed striae of the band are -"isible, but also the 

 shoulder around the suture on the body-whorl, the transversely 

 elongated, oblique, rhomboidal mouth, and thickened inner lip. 



Dana also described a second species of Platyschisma from 

 the Lower Marine Series as P. depressum, Dana, sp.'' Some 

 imperfect individuals have come under my observation that may 

 be this form, and if this surmise be correct, then possibly a 

 second species of Keeneia exists. In such a case, a further 



3 Dana— Wilkie's U.S. Explor. Exped., Geology, x., 1849, pi. x. , f. 1. 



4 Etheridge, Junr.— Rec. Geol. Surv. N. S.W., v., pt. 4, 1898, pi. xix., f. 

 14 - 17. 



5 Dana — Loc. cit., pi. x., f. 2 a and h. 



