Remarks upon the Genus Anomalodonta, etc. 327 



posed to use the name Ophthoptera as a substitute in case such objec- 

 tion should arise. Indeed, I am informed by a friend that Mr. Meek, 

 in his work, now in manuscript, has decided to use the name Ojns- 

 thoptera Casei and 0. alctta for Mrgaptera Casei and M. alata. 



The fact that Meek and Worthen did not describe the hinge of 

 Megaptera, which was unknown to them, in their generic diagnosis, 

 has no bearing upon the question of priority. If it were otherwise, 

 few genera of fossils would be allowed to stand after the discovery of 

 more perfect specimens than the original workers possessed. Nor does 

 the fact that Meek and Worthen called theirs a subgenus affect the 

 question, for the rule covers such cases as well as others, and the use 

 of such a designation under similar circumstances indicates on the part 

 of an author a degree of caution that all true naturalists will approve. 



Further, upon comparing Mr. Miller's description of his species 

 gigantea with Meek's alata, I am unable to find that the former possesses 

 characters sufficient to separate it specifically from the latter. Mr. 

 Miller seems to have relied solely upon the large size and the preserva- 

 tion of concentric stria; of his shell to separate it from M. aJata. As 

 Mr. INIeek distinctly mentions the existence of the striae in his shell, 

 Mr. Miller's species seems to be reduced to the very insufficient ground 

 of size alone. C. A. W. 



I presume, from the initials, that the author of the foregoing criti- 

 ' cism is. Prof. C. A. White. In answer to it, I shall, first, call atten- 

 tion to the fact, that the Professor is unable to find, that the species 

 gigantea possesses characters sufficient to separate it specifically from 

 the alata. This difficulty, which he has encountered, may be owing 

 to the imperfect description, by Prof. Meek, of the alata, or to ray im- 

 perfect description of the gigantea. It certainly is the fault of one of 

 us, or his own mistake, for the specific differences are so strongly 

 marked as to leave no doubt upon the subject. 



I am inclined to think that it is his mistake, for, however imperfect 

 the descriptions may be, a glance at fig. 9, on page 18, of the January 

 number of this Journal, and fig. 10, plate 12, of the Ohio Paleontology, 

 ought to have suggested some important specific differences, even to a 

 tyro in paleontology. But let us compare the descriptions of the 

 surface markings as pubdislied : 



1, Gigantea. — " Surface marked by 30 to 40 strong radii, same width 

 as intermediate spaces, which are concave grooves, marked with con- 

 centric striae, giving much the same external appearance as those of 



