284 GyHoceras magider. 



"As to the affinities of Amhomjchia with the AvimUdce, which Mr. 

 Miller rufuses to admit, on account of the equality of the valves, I need 

 only to remark that to make such family distinctions as that proposi- 

 tion, would require us to divide well defined genera, some species of 

 which would fall in one family and some in another, the genus 

 Inocerarmis being an example. The true (Triassic typical) Monotis, 

 Halohia, and others are included by the highest authorities among the 

 Aviculidse, and yet they are equivalve. He refers to McCoy as the 

 first to refer Amhomjchia to the Aviculidse, being evidently unaware 

 of the fact that in 1833, Goldfuss in his great work, Petrif, Germ., did 

 the same. Conrad, Woodward, Brown, Dr. Carpenter, and Dr. 

 Stoliczska all have done the same, the latter even placing it near 

 Avicula in the section Aviculinje." 



The genus Amhomjchia was formed by Prof. Hall, and first pub- 

 lished in 1847. Goldfuss described Pterinea carinata, which was 

 removed afterward to the genus Amhomjchia. Prof. Meek discussed 

 this matter of the family relations of these shells in his work on the 

 Paleontology of the Upper Missouri. He divided the family Pteriidce^^ 

 Avicididce into three sub-families, viz.: Pteriniinoe,, Pteriiim and 

 Melinince. In the first of these sub-families he placed Myalina and 

 Amhomjchia, and he placed Avicula in the second sub-family. If his 

 sub-families were raised to the grade of fixmilies, it would seem to me 

 to be a better classification. In other words, Prof Meek would place 

 Amhomjchia, Myalina, Anomalodonta, etc., in a sub-family, distinct 

 from the Aviculince, while I infer from the above that Prof, \yhite 

 would not. 



Cyrtoceras magister — (S. A. Miller.) 



In the April number of this Journal, page 132, a new species of 

 Cyrtoceras was described under the name of ohscurum (by mistake 

 ohsGura), since that time, I have learned that Barrande had already 

 described a fossil, under the name of Gyrtoceras ohscurum, and conse- 

 quently, I had no right to use the word. I now propose for that 

 species, the name Cyrtoceras viagistei'. 



There are two other mistakes in that monograph of the Cephalopoda 

 that might as well be corrected here. Orthoceras transversa sliould 

 have been written, Orthoceras transversum, and GyHoceras vcntricosa 

 should have been written GyHoceras ventricomm. 



