34 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. "J}^ 



OPINION 130 



Lytoceras Suess, 1865, Placed in the Official List of Generic 



Names 



Summary. — Under Suspension of the Rules Lytoccnis Suess, 1865 (genotype, 

 Ammonites fimbriatus Sowerby) is hereby placed in the Official List of Generic 

 Names. 



Statement of case. — The following cases have been submitted by 

 Dr. L. F. Spath : 



Ophiceras was proposed by E. Suess in June, 1865, (Anzeiger K. Akad. Wiss. 

 Wien, p. 112) for the " fimbriati " (i. e., group of Ammonites fimbriatus Sowerby) 

 but was afterwards thought to clash with Ophioceras Barrande (May 1865, in 

 explanation to plates, =i Ophidioceras Barr., in text, 1867) and was replaced 

 later in 1865 by Lytoceras Suess (Sitz. B. Akad. Wiss. Wien, vol. 52, p. 78). 

 This last has ever since been in universal use. 



A second Ophiceras was proposed in 1880 (Griesbach, Rec. Geol. Surv. India, 

 vol. 13, p. 109) for a Triassic group of ammonites, and (Suess' original Ophiceras 

 being forgotten) it has now also become universally accepted. 



The resuscitation of the original Ophiceras according to the Rules of Nomen- 

 clature would cause great paleontological confusion. Lytoceras and the family 

 Lytoceratidae are now given in every textbook, Lytoceras being one of the two 

 fundamental ammonite genera, persisting from the base of the Lias to the Upper 

 Cretaceous. Ophiceras, also recorded in most textbooks, is Lower Triassic in 

 age, so that from stratigraphical considerations, also, it would be advisable to 

 secure stabilization of the present use of these two genera by the International 

 Commission as follows : 



Genus Lytoceras Suess, 1865 (genotype: Amiiioiiites fimbriatus Sowerby ; Min. 

 Conchol., vol. 2, pi. 164, 1817). 



Genus Ophiceras Griesbach, 1880 (genotype: O. tibeticum Griesbach, 1880, 

 p. 109, pi. 3, fig. 4). 



Discussion. — These cases were referred to Commissioner Bather 

 for special study. He reported upon them as follows : 



I have gone into this case carefully and consider it to be eminently one 

 where adherence to the rules would produce nothing but confusion. I therefore 

 recommend as the Opinion of the Commission: That, to prevent confusion, the 

 law of priority be suspended as regards Lytoceras Suess, 1865 (genotype. 

 Ammonites fimbriatus Sowerby) and Ophiceras Griesbach, 1880 (genotype, 

 O. tibeticum Griesbach) and that these two names be added to the Official List of 

 Generic Names. 



The documents in question were then submitted to Dr. B. B. Wood- 

 ward, and to the following Museums : United States National Mu- 

 seum, Washington, D. C. ; Senckenbergische Naturforschende Gesell- 



