﻿252 



Cincinnati Society of Natural History. 



1 88 1. Whitfield, R. P. Observations on the purposes of the embryonic 

 sheaths of Kndoceras, and their bearing on the origin of the 

 siphon in the Orthocerata. In Bulletin No. i of American 

 Museum of Natural History (Central Park, New York), page 20. 

 In this the writer examines the theory of the embryonic nature of the 

 sheaths of Endoccras, and concludes against it. He fully describes the features 

 presented by the duplicate siphons. Various specimens show that while the 

 animal occupies the outer chamber, part of the body extends into the 

 siphonai cavity in the shape of a long, loosely-hanging finger. "These 

 sheaths were not only formed in case of accidents already having taken 

 place, but were probably often formed to guard against future troubles." 

 (P- 23). 



1 88 1. Miller, S. A. Journal of the Cincinnati Society of Natural 

 History. Vol. IV. 

 Notice and figures of Orthoceras byrnesi^ 0. fostcri. O. diicinnaticnsc, 



O. Jiarpcri (see 319), (see under O. dyeri). 



1883. Tryon, Geo. W. Structural and Systematic Conchology. Phila. 

 In volume II on pages 13, 26, 27, 33, 45 to 48, and 50 to 87 are 



descriptions of the genera and sub-genera of fossil cephalopods. There 

 are figures of many of the genera. The descriptions are short and in 

 some cases in almost the same words as in Woodward's Manual. 



1884. Miller, S. A. Journal of the Cincinnati Society of Natural 



History. Vol.* VII. 

 Descriptions of Gomphpceras faben and G. cincinnaiUnse (page 19). 

 1884. Hyatt, A. Genera of Fossil Cephalopods. In Proceedings of 

 Boston Society Natural History. Vol. XXII. 1883. (Pub- 

 lished Jan., 1884.) Page 253 and ct scq. 

 This paper, occupying eighty-five closely printed octavo pages, is, 

 we are told, "preliminary to a monograph which will appear in the Me- 

 moirs of the Museum of Comparative Zoology/' In it the author has 

 attempted to arrange the genera of fossil cephalopods according to a 

 graded series, from the first straight chambered shells (Orthoceras) through 

 the arcuate (Cyrtoceras) , the loose coiled (Gyroceras), to the close coiled 

 (Nautilus). " The generic terms Cyrtoceras, Gyroceras, Nautilus, are," 

 he says "really only descriptive terms for the different stages in the 

 development of an individual, and also the different stages in the develop- 

 ment or evolution of the series of adult forms in time. In other words, 

 each of these genera are now used to indicate representatives of all the 

 different generic series of Tetrabranchs, which are either young shells in 

 the corresponding stage of growth, or adult shells in the corresponding 

 stage of evolution." (Page 254.) 



