240 NATURAL SCIENCE [April 



book, " The American Lobster/' and the review of that book which 

 appeared in Natural Science for June, 1896. Dr Herrick's advisers 

 on the subject were Dr Walter Faxon and Miss Mary J, Rathbun. 

 They have since returned to the attack.^ 



Dr Walter Faxon is, I believe, the greatest living authority 

 on crayfishes. Miss M. J. Eathbun is one of our foremost 

 authorities on crabs. Both these writers are distinguished for 

 their learning, industry, and acuteness. To see them both relying 

 on Latreille's feeble book is like contemplating the first Napoleon as 

 Emperor of Elba. In the outset these eminent naturalists were 

 confessedly under the impression that, in writing my " History of 

 Crustacea" (Internat. Sci. Series, 1893), I had overlooked Latreille's 

 "Considerations Generales " of 1810, whereas, in point of fact, I had 

 given them my particular consideration and had, then as now, come 

 to the conclusion that on questions of nomenclature, the book con- 

 taining them was of no importance. 



It will probably be admitted on all sides that when an author 

 establishes a genus for a single species, that species must be 

 regarded as the type of the genus. It will probably be further 

 admitted that, of several species contemporaneously placed in a 

 genus, any one singled out by the author himself as the type of the 

 new genus holds a preferential right to the generic name. But, sup- 

 posing that the author has not selected a type, and that the species 

 of his genus have eventually to be re-distributed among several 

 genera, which of them is then entitled to be retained in the original 

 genus ? Apart from other guidance, might not one innocently 

 suppose that the species placed first by the author ought to have 

 precedence ? It has priority, even if it be on the same page with 

 its successors. I ask whether one might not innocently suppose 

 this, because the innocence of the supposition is called in question 

 by Dr Faxon. He says : — 



" It is hard to believe that this contention of Mr Stebbing's is 

 made in good faith, involving as it does an unreasonable and long- 

 discarded method of ascertaining a type. Such a method is re- 

 pudiated every time we concede to an author, who first sub-divides 

 a genus in which no type has been specified, the right to restrict 

 the original name to such part of it as he pleases. It is not true 

 that the first species is presumably the author's implied type. 

 Fabricius's genus Astacus was formed by a dismemberment of the 

 genus Cancer of Linnaeus, and the sequence of the two species under 



1 A revision of the nomenclature of the Brachyura, by Mary J. Rathbun. Proc. 

 Biol. Soc, WashiiKjton, vol. ii. pp. 153-167. 1897. 



List of the Decapod Crustacea of Jamaica, by Mary J. Rathbun. Annals of the 

 Inditute of Jamaica, vol. i. , No. 1. 1897. 



Observations on the Astacidae in the United States National Museum and in the 

 Museum of Comparative Zoology, witli descriptions of new species, by Walter Faxon. 

 Proc. U.S. Nat. Mas., vol. xx., No. 1136. 1898. 



