Twenty-fourth annual Meeting. 



41 



ders and on the abrupt edges of the abdomen. The abdominal lobe is short and 

 broad. It has a slight angle or V- shape in the specimen, but this is probably due 

 to compression. The sutures just inside of the umbilical shoulders appear to be 

 nearly straight on the nearly vertical narrow zones on either side of the outer whorl, 

 but there is probably a shallow dorsal lobe on the impressed zone. The living 

 chamber is about one-fourth of a volution in length, and still incomplete. The 

 specimen is much narrowed by compression, apd, making due allowance for this, 

 the abdomen is slightly broader than the dorsum, measuring through the umbilical 

 shoulders, and it has been so represented in the drawing. The arnount of involu- 

 tion is slight, the whorls being in contact only along the surface of the slightly con- 

 vex abdomen, and there is, consequently, only a shallow impressed zone in the dorsal 

 surface of each whorl. Nevertheless, the increase by growth in the dorso-abdominal 

 diameter of the whorl is evidently rapid. 



Specimens of this and some other species were received through the courtesy of 

 Capt. George E. Pond, of Fort Riley, Kas. 



The front view (fig. 9) is in large part restored from a much-compressed speci- 

 men. 



Its nearest ally occurs in the carboniferous in Russia. It differs from Metacoceras 

 {Nautilus) Tschernyscheiui Tzwetaev, [see Ceph. du Calc. Carboniffere de la Russie 

 Centrale, Mem. du Com. Geol., V, No. 3, pi. 2, figs. 7-9,] in having somewhat broader 

 sides and a narrower abdomen at the same age, and fewer tubercles. These also are 

 elongated longitudinally, whereas in Tschernyschewi they are elongated transversely, 

 forming a series of rib-like folds. 



Metacoceeas inconspicuum, n. s. 



Loc, Kansas. 



Coll. R. Hay. 



Figs. 10 and 11, natural size. 



This cast has an aspect which 

 at first sight leads one to think 

 it is a species of Tainoceras, but 

 the abdominal sutures are defi- 

 cient in the pair of saddles dis- 

 tinguishing that genus, and there 

 are no lines of abdominal tuber- 

 cles. The whorl increases in ab- 

 domino-dorsal diameters faster 

 than Metacoceras cavatiformis, 

 but not in the transverse diam- 

 eters; the whorl is, consequently, 

 more compressed. The umbili- 

 cal shoulders are not so angular 

 as in that species, and the sides 



broader and 





less converg- 

 ent outwards, 

 and the tuber- 

 cles upon the 

 outer border 



of the sides are less conspicuous upon this cast. The sutures 

 have about the same general contour as in the nearest ally just 

 mentioned, but the lateral lobes are broader and shallower, and 



Fig. 10. 



