138 RECORDS OF THE AUSTRALIAN MUSEUM. 



III. — The Names Crioceras and Ancvloceras. 



Before proceeding with the specific descriptions, it may be well 

 to pass in review some facts in the history of these genera. 

 Leveille's original description as Crioceratites is not available, 

 and I have to fall back on D'Orbigny's, ° which is a very wide 

 definition. The principal features of his Crioceras, irrespective 

 of the sutures, were a discoida] form, the coil enrolled in one 

 plane, the whorls non-contiguous, and an oval, round, or com- 

 pressed mouth. From the figures, the first of which is Leveille's 

 type (C. duvalii), we learn these interesting facts, viz., the 

 increase in the circumference of the whorls was comparatively 

 slow and slight, the coil a very open one, and in the type three 

 rows of tubercles on each side the middle line of the venter. 

 D'Orbigny's Ancyloceras so closely resembles Crioceras in its 

 earlier stages that Mr. J. E. Astier 7 united the two, in which he 

 was followed by Messrs. Pictet and Campiche, but unfortunately 

 they selected the former name, thereby denying to Leveille's 

 genus its undoubted priority. Palaeontologists have since used 

 both names, some one and some the other. The whole question 

 is excellently and clearly put in favour of Crioceras by Messrs. 

 Sarasin and Schondelmayer, to whose remarks* the reader is 

 referred, but they point out that the genus Crioceras is, amongst 

 all the genera of Ammonitidae, one of those interpreted very 

 differently by authors. Amongst those who are in accord with 

 the above authors are Messrs. M. Neumayr, M. Neumayr and V. 

 Uhlig, and E. Haug. 



The difficulty appears to have been to find some satisfactory 

 method of division into genera of the heterogeneous assemblage 

 of forms previously known as Crioceras, to replace the old 

 D'Orbignyan one of degree of enrolment. The artificial nature of 

 this method was, I believe, first pointed out by Dr. M. Neumayr, 

 who suggested a division of the Ammonitidse on the basis of 

 natural kinship, to some extent then already foreshadowed by 

 Quenstedt and Pictet. 



Neumayr and Uhlig described 9 three lines of development of 

 Crioceras forms from Ammonite stocks — one from Olcostephanus, 

 viz., C . Jissicostatum ; a second from Hoplites (H. /n/strix), viz. r 

 C. roemeri, N. & U.; and the third also from Hoplites {11. 

 longinodis), \iz., C. seeleyi, N. & I'. These authors did not 



6 D'Orbigny— Pal. Knim; Terr. CivL, i., Ceph., p. 475. 



A stier— Ann. Sci. I'hys. Nat. Soc. Nat. Agric Lyon, (2), iii., 1851, p.435 

 8 Sarasin anil Schondelmayer— M6m. Soc. Pal. Suisse, xxix., 190'2. p. 99. 



Neumayr and Uhlig — Palaeontographica, xxvii., 3-t*>, 1881, p. 184. 



