326 RemarJcs upon the Genus A)wmalodonta, etc. 



Bemarks upon the Genus Anomcdodonta and the words 3Iegaptera and OpU- 

 thopteni, and the species gigantea and alata. [From the American 

 Journal of Science and Arts, for September, 1874.] 



In the first issue of the Cincinnati Journal of Science, I observe 

 that the editor, Mr. S. A. Miller, proposes a new genus under the 

 name of Anomalodonta, to include a group of shells allied to Amhony- 

 chia of Hall. These shells constitute a very interesting type, evidently 

 belonging to the family Aviculidae. Like Amhoni/chia, they are desti- 

 tute of an anterior wing, but have, posteriorly, a very large one, which 

 gives the shell a trigonal outline. Mr. Miller's type specimens show 

 them to have a broad striated area, such as Myalina possesses, with, 

 at the anterior end of the hinge, an oblique fold or ridge, not properly 

 a tooth perhaps, together with a corresponding depression in one or 

 both valves. We see just such characters in the broad forms of Mya- 

 Ilna, as for example in M. ampla of Meek and Hayden, so that, 

 although generically distinct from Mr. Miller's shell, there seems to be 

 little to distinguish the latter, except outline and radiating costa3, un- 

 less he is right in stating that his shell has a large impression of the an- 

 terior adductor muscle, which, in view of the affinities of the shell, is 

 very impi-obable, especially so large an impression and in so loAV a posi- 

 tion as he has figured it. Compared Avith Ambonychia, the hinge of 

 his shell differs materially, in wanting the two anterior well defined 

 teeth of that genus and also its three elongated posterio-lateral teeth. 



This genus Anomalodonta was proposed for a group of shells identi- 

 cal with the one for which Meek and Worthen proposed the subgeneric 

 name of Megaptera, in the Proceedings of the Chicago Academy of 

 Science in 1866. Mr. Miller himself states that his proposed genus 

 Avill include Ambonychia {Megaptera) alafa Meek (Ohio Paleon 

 tology, vol. i., p. 131), of which he says Mr. U.P.James has specimens 

 showing the same hinge characters. He also states that his proposed 

 genus will include, among others, Megaptera Casei of Meek and 

 Worthen, which is the type species of Megaptera. In short, he pro- 

 poses a new genus to include the type of a previously established one, 

 together with another species of the same, described by one of the 

 authors of the forenamed genus. Megaptera has unquestionable 

 priority, and must stand before Mr. Miller's name and all others also ; 

 unless, however, the name Megaptera may be objected to on account of 

 its previous use by Dr. Gray for a genus of whales. Even in that 

 case Mr. Miller's name could not stand, because Mr. Meek, in the 

 Proceedings of the Philadelphia Acadamy Natural Sciences, 1872, pro- 



