APPENDIX. 293 



more than once we find tte same species figuring in two genera 

 with the same references in each instance ! It is a most disap- 

 pointing book. Trusting to the traditional fame of Leach, as a 

 malacologist, we had expected to find that when reasons were un- 

 discoverable in the shells only, there were good ones derived from 

 observations on the soft parts, or anatomical researches, for the 

 numerous genera, the names of which are preserved in cabinets, 

 or ticketed, to the perplexing of beginners, on specimens in the 

 British Museum. We had imagined to ourselves sound though 

 occult reasons weighing in the mind of Mr. Gray, when he so often 

 adopted these mysterious appellations in preference to the terms 

 of published nomenclature. Greatly were we surprised to find, 

 now the murder is out, that Leach constituted these genera on tri- 

 vial distinctions, exhibited by the shells only ! The strangest com- 

 binations result, and animals that are toto coelo distinct, are bound 

 together by almost imperceptible links. Let any zoologist turn 

 to Leach's family of Tii,rbonidce, and see if our censure be not far 

 too mild. The descriptions of the species are vague, meagre, and 

 poor indeed, and for this there could be no excuse, since the accu- 

 rate and perspicuous Montagu had already written to serve as a 

 model. But far more censurable than these errors of judgment is 

 the unaccountable recklessness with which new names are given to 

 well-known and well-named species, without the shadow of a rea- 

 son why ; and, except in very rare instances, without an apology 

 for the proceeding. The supposed new species that are described, 

 unless traditionally known, are undiscoverable, and most of them 

 must remain so. So far as the Tunicata and Nudihranchiata are 

 concerned, little harm will be done, since in these cases the work 

 will be treated as so much dead letter. But injudicious collectors 

 and curators may be tempted, from the love of change or the 

 vanity of differing from accepted usage, to make use of Leach's 

 nomenclature. To prevent mischief as much as possible, we 

 append, in default of editorial notes, a concordance for the tes- 

 tacea. If we have been severe in these comments, it is because 

 we feel compelled reluctantly to protest. At the same time we 

 must express our belief, that, with matured thought and better 

 health, the work would have been sent forth by its author in 

 a very different shape. 



