FROM AEISTOTLE UNTO THIS DAY 203 



The first pair of trunk-legs are large, robust, markedly un- 

 equal. The type-species is Astacus gammarus (Linn.), which 

 Milne-Edwards and Bell speak of as Homarus vulgaris. 

 Occasionally this is corrected by authors into Homarus 

 gammarus. Spence Bate admits that Leach has un- 

 doubted priority, but regrets that to acknowledge his 

 claim would only have the result of creating great con- 

 fusion, which Leach himself would have deprecated, and 

 that it would introduce terms not likely to be generally 

 accepted. The sentimental consideration that Dr. Leach 

 would deprecate a particular result may be dismissed, 

 since in natural history the author of a name once pub- 

 lished has no more control over it than any other person. 

 In the due recognition of priority there is probably a 

 better chance than any other principle affords of eventually 

 clearing away confusion. No doubt, to our eyes, the age 

 of Leach, as far as Crustacea are concerned, seems a kind 

 of primitive antiquity, but in the perspective of another 

 century or two the writers of to-day will seem to stand 

 close by his side or very little in front, and if our nomen- 

 clature is carried out without principle, we must expect to 

 be treated like the pre-Linnaean zoologists, and have our 

 nomenclature put altogether out of court. It may be 

 mentioned that Adam White, a considerable authority in 

 his time, uses the name Astacus gammarus for the lobster, 

 in his ' Popular History of British Crustacea,' published 

 in 1857, thus showing that he was not to be daunted or 

 led astray by the authority either of Milne-Edwards or of 

 Bell. Leach remarks that ' Aristotle has very distinctly 

 described this species under the name aa-ra/cos.' He is 

 referring no doubt to the very interesting but rather per- 

 plexing second chapter of the fourth book of Aristotle's 

 ' History of Animals.' 



Astacus americanus (Milne-Edwards) closely resembles 

 the European species, but has two spines on the under 

 surface of the rostrum, which are wanting in its congener. 

 It is, like the other, a large and extremely prolific species, 

 much sought after for food. It is reckoned that a million 

 a year are consumed in Boston alone. Professor S. I. 



