352 GEOLOGICAL SURVEY OF TEXAS. 



Koninck, but there can be no certainty in the comparison of figures, which 

 are mere sketches. The latter is, however, less involute than the former, and 

 this suggests comparison with De Verneuil's clitellarius. 



Comparative length of living chamber can not be given because of the ab- 

 sence of the inner whorls. 



There are two specimens of Ephippioceras in Prof. Newberry's collection at 

 Columbia College, New York, coming from near Kansas City, Missouri, which 

 may be the young of this species. One of them exhibits a living chamber, 

 complete above on the abdomen, which is over one-fourth of a volution in 

 length. 



The specimens of Ephip. (Naut.) /erratum from Kentucky, in Coll. Museum 

 Comp. Zool. at Cambridge show that this shell has a rounded very gibbous 

 sided whorl with the central parts of abdomen also rounded, as in Fig. 2a on 

 PI. X of the Atlas of volumes II and III of Report Geological Survey of 

 Kentucky. The increase in the transverse diameter is slower in this species 

 than in E. divisum at any age. 



A fragment in Coll. Geological Survey of Texas belongs to a specimen of 

 this species and exhibits the same very prominent abdominal saddles in the 

 sutures and rounded abdomen The size of this is intermediate between the 

 two above described and the large one from Kansas. 



Ephippioceras (Nautilus) Montgomery ensis* (sp. Worthen) differs from this 

 species and all others, if accurately figured, in the tongue-like outlines of the 

 neutral saddles. The umbilical shoulders are also peculiar. 



ENDOLOBUS. 



This genus has been sufficiently described in Genera of Fossil Cephalo- 

 pods.f 



The species described has not at the latest stage of growth in the single 

 specimen observed yet acquired the ventral saddles found in other species. 

 The slight ventral lobes are retained apparently even in adults. Figure 33 is 

 taken from the young whorl after the removal of the living chamber. Fig. 

 34 shows a section of all the whorls observed in the same specimen, with an 

 outline of the internal part of the suture, exhibiting the annular cone in 

 section. 



Endolobus (Solenocheilus) Indianense, if correctly figured, has the siphuncle 

 nearer the abdomen than is usual in this genus, and the whorl in section has 

 a very peculiar helmet-like shape, owing to the depression of the sides and the 

 consequent narrowing of the abdomen. 



*Geol. Surv. 111., VIII, PI. 26-27. 

 f Op. cit., p. 288. 



