TWENTY-FOUBTH ANNUAL 3IEETING. 45 



ASYMPTOCEBAS NeWLONI, n. S. 



Loc. Oswego, Kas. Coal measures. 



Coll. Nat. Mus., Dr. Newlon. 



The species in hand is a fragment very similar to As. (Cryptoceras) capax Meek 

 and Worthen. [See Geol. 111., VI, p. 532, pi. 33, fig. 1.] There are three air cham- 

 bers incompletely preserved in the cast. The last two sutures are 17 mm. apart on 

 the venter. The increase in size is very rapid, being as much as 46 mm. in the 

 greatest transverse diameter, to 68 mm., a difference of 22 mm. in a distance of only 

 51 mm. as measured along the center of the venter, and only 35 mm. as measured 

 along the side of the whorl. 



These measurements show a more rapid increase than in the whorl of Asynipt. 

 capax. The sutures are not only wider apart than in that species, but the form of 

 the whorl also differs. In the figure of As. capax. the greatest diameter of the living 

 chamber is above or external to the umbilical shoulder, whereas in this species it is 

 at the umbilical shoulder. The sides converge outwards from these shoulders and 

 are not gibbous as in capax; and in the living chamber, which is evidently very 

 nearly complete on one side, the whorl becomes flatter or more depressed on the 

 abdomen than in capax, and the flaring of the aperture at the umbilical shoulders 

 carries the lateral angles out with great rapidity. The diameter through the widest 

 part of the whorl at the last suture is 68 mm., at a point about half way between 

 this and the aperture about 82 mm., through the wings themselves not less than 120 

 mm., and perhaps a little more in perfect specimens. 



The sutures have a distinct, but very shallow, broad lobe on the venter, which is 

 irregularly interrupted by the siphon, and there are also shallow lateral lobes. In 

 some specimens the sutures are very likely continuous, as they are in the figure of 

 capax. If the side view of the sutures in the figure of capax is correct, these differ 

 decidedly from those of this species. This shell differs from Asym. Springeri in 

 having less angular umbilical shoulders, a more depressed abdomen, and more con- 

 vergent sides. In fact, Springeri and capax resemble each other more than either 

 of them resemble this species. [The species has been dedicated to Dr. W. S. Newlon, 

 of Oswego, who found and sent the specimen, with some others described in this 

 paper, to the National Museum.] 



The comparative length of living chamber cannot be given, since the inner 

 whorls were not visible. 



Phacoceeas Dumbli, n. s. 



Texas. Coll. Geol. Surv. of Texas. 



Fort Riley, Kas. Coll. R. Hay. 



The extraordinarily large size of this shell, its involute form, its compressed 

 whorls, and the attenuated character of the outer part of the whorls in proportion 

 to their transverse diameters, combined with the comparatively smooth and ribless 

 shell, make this species interesting. 



The umbilici are very narrow and small, the involution being almost complete. 

 The increase of the vertical diameters by growth is extremely rapid, whereas the 

 transverse diameters have increased very slowly, leaving whorls very much com- 

 pressed or axe shaped. The broadest transverse diameters are near the umbilici, 

 and from this part the whorl is slightly concave on both sides towards the periphery 

 or abdomen. This, although very narrow, is flattened or slightly convex, even in 

 the largest specimens. 



The living chamber in one specimen was about one-half of a volution in length. 

 The lines of growth indicate that the aperture probably had very broad lateral sad- 

 dles and a single deep, narrow, median abdominal lobe. 



