GENUS ATHYRIS. 2G3 



"sidered typical by the author." Now what is the typical portion of the 

 genus in this instance ? Mr. Billings talks of the typical figure, which 

 is given without a name, and therefore impossible of reference. We think 

 there is another rule, which, if not as concisely expressed as that above, is 

 nevertheless usually followed ; and this is, that where the author neglects 

 to indicate the type of his genus, the first described species under it shall 

 be taken as the type. Mr. B. cites some observations preceding the rule 

 quoted above, which he says should be embodied in it, and intimates that 

 this "rule bears directly on the question, because many naturalists are 

 " under the impression that the first species placed on the list must necessa' 

 *' rily be regarded as the type, where the author is silent on that point. But 

 "according to the above (and common sense), it is only so if found 

 *' accurately to agree with the definition. Spirigera concentrica does not 

 " agree either with the name Athyris, nor with M'Coy's generic descrip- 

 *' tion, nor with his typical figure* Therefore it cannot be arbitrarily 

 *' selected as the type, and the name Athyris, in consequence, retained for 

 " that group. Indeed in many instances it would be impossible that the 

 " first species placed in the genus should be the type, for the author might 

 " not have the true type in the collection under investigation." That an 

 author may describe a genus, and " not have the true type in the collection 

 under investigation^'' seems a little latitudinarian ; and so perhaps he may 

 abandon all he has at first placed under the genus, and at some later day 

 claim something else as his type. We have had a little of this sort of 

 work in Palaeontology of late years, with generic descriptions broad enough 

 to include whatever you please, and indefinite enough to be shifted to any 

 form that subsequent exigencies might require. 



In the present case, Prof. M'CoY has asserted that the beak of A. 

 concentrica is often closed ; and yet Mr. Billings asserts that he could 

 not have intended A. concentrica^ because his description and typical 

 figure do not accord with that species ; and in order to prove that the beak 

 is not closed, he has -copied A. concentrica "with the aperture in the beak 

 " made larger than it is in the original figure." Can a genus be founded on a 

 " typical figure^ ^ winch is given without name or description ? 



I have occupied more space with these remarks than I intended ; and 

 I should not have noticed the article at all, but for the suggestion of an 

 author whose opinion I value. I cannot help the conviction that a critical 

 study of interior structure will aid us much more than long discussions 

 on nomenclature ; and believing that our knowledge in this respect has 

 been somewhat advanced within the past few years, I shall concern 

 myself very little regarding this question of words. Before leaving the 

 subject, however, I may remark that Mr. Billings, in the concluding 

 pages of his paper, cites his own previously published opinions to 

 strengthen the case that was so well fortified by collateral support in the 



* Athyris concentrica agrees with the generic description of 1844 — perhaps not with 

 that of 1852, unless we add the correction of Prof. M'Coy, cited on the preceding page. 



