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der anderen Seite. keine eigene, festere, verkalkte Hulle gehabt zu 

 haben." If the siphuncle were holochoanoidal, it would have as 

 thick and might have thicker walls than the septa themselves. 



A list of the species is as follows, as given byNotling: A. undu- 

 latum, Boll. ; Torelli, Rem.; Barrandei, DeWitz.; Bolli, Rem. To 

 these Notling has also added Cryt. Odini, Eichwald (Lethea Ros- 

 sica, PL xxvi, Fig. i^a-fr), and he thinks this may be identical 

 with undulatum. 



Ancistroceras (f) Dyeri, n. s., is a large fragment quite different 

 from any European species, having the sutures with slight broad 

 ventral lobes, slight saddles at the abdominal angles, lateral lobes, 

 saddles at the umbilical shoulders, and apparently narrow dorsal 

 lobes. 



The fragment is that of a rapidly enlarging arcuate whorl, sub- 

 quadragonal in section, the lateral zones slightly convergent out- 

 wards, the dorsum broader than the venter. 



The siphuncle is ventrocentren. 



The lines of growth seen on the living chamber had the charac- 

 teristic ventral sinus, slight crests on the abdominal angles, slight 

 lateral sinuses, broad low crests on the umbilical shoulders and in- 

 ternally faint minor dorsal sinuses apparently rising to an equally 

 faint median dorsal saddle. 



It has characteristics which appear to be intermediate between 

 Ancistroceras and Rhyncorthoceras. This fossil is from the Niag- 

 ara Group near Chicago, 111., Dyer collection, Mus. of Comp. 

 Zoology, and is worth describing in this connection, although until 

 it can be studied in the young and figured it is hardly safe to refer 

 it to this genus. It has been named Cyrioceras amplicome, Hall, 

 and closely resembles that species, but the section is more decidedly 

 quadragonal, the sides and venter flatter and the transverse diame- 

 ter broader. 



Rhyncorthoceras. 



The designation Rhyncoceras has also been used by Remele and 

 others, but Rhyncorthoceras was used first, and should be exclusively 

 employed. Rhyncoceras is not an equivalent, and there cannot be 

 two names for one genus. 



Remele's description of this genus is perfectly clear and satis- 

 factory. It is in my opinion another grade in morphic degenera- 

 tion of the Lituitidae, and is directly in line with and supplementary 



