354 Miscellaneous. 



sentiment is sound, it is not well but ill expressed. There was no 

 need for a confusion of languages in the macaronic style, nor for 

 comparing the definite and well-known year 1758 s'ith the di:<puted 

 and uncertain date of the foundation of Rome. But I fear that 

 Professor Bell only asked the question mischievously, to lure me 

 into " gibing," as he calls it, at some fearfully eminent person. 



(iv., V.) It seems essential once more emphatically to explain 

 that Desmarest never mentions Potamohius at all, though Professor 

 Bell, misquoting himself as well as Desmarest, insists that he does. 

 In his first paper the professor accurately cited Uesmarest's sugges- 

 tion that Potamohia of Leach might be the same as the river-crab 

 Thelphusa. Now he persuades himself that Desmarest definitely 

 said that " Leach's Potamohhis was a river-crab." Leach, in 1818, 

 applied a French name — Potamohie — to some genns of crustaceans, 

 but without a single word of description ; so that, had the name 

 been valid in form, it would still have been absolutely without any 

 scientific importance. In 1823 Desmarest Latinizes the name into 

 Potamohia, and hazards a guess at the application intended. Mean- 

 while, inl819, through Samouelle's 'Compendium,' and very obviously 

 without the knowledge of Desmarest, Leach had assigned the cray- 

 fish to a properly constituted genus Potamohius. Now, lastly, in 

 1897 Professor Bell apparently wishes us to believe that Potamohiits 

 was somehow preoccupied in 1819, because Desmarest made a 

 casual allusion to a wholly indefinite Potamohia in 1823! 



(vi.) From the solemn severity of tone in his closing paragraph 

 it seems as if Professor Bell imagined that his reputation as a 

 naturalist was involved in this discussion. Ho should not harbour 

 such a thought. The controversy has been, not about nature, but 

 about names. From Leach's ' Malacostraca Podophthalmata Bri- 

 tannia),' as completed in recent times by Mr. G. B. Sowerby, it will 

 be seen that I have been fighting on the side of a long line of 

 authorities of the British ^Museum, Professor Bell, out of charity 

 or out of friendship, should allow this to weigh in the balance 

 against the sad ofteiice — of which he hopes (perhaps against hope) 

 that 1 have by this time rejienled, — the unwitting otifence of gibing 

 at men of renown, living and dead, infallible, authors of text-books. 



Nocturnal j^rotcctive Coloration in Jllammals, Birds, Fishes, Insects, 

 4'c., as develojnd hy Natural Selection *. By A. E. Verrill. 



Much has been written in respect to the imitative and protective 

 colours of these groups, as seen by daylight, and the bearing of 

 these facts on natural selection is well known. Very little attention 

 has been paid to their colours, as seen by twilight, moonlight, and 

 starlight. Yet it is evident that jirotection is more needed diiring 

 the night than in tlie daytime by a very large number of species. 

 This is the case with those that move about in search of their food 

 at night, as is the habit of numerous forms of small mammals, such 

 as rodents (rats, mice, arvicola>, &c.), insectivores (moles, shrews, 

 &c.), many herbivores, various marsupials, and members of other 



♦ Abstract of a paper read before the Morphological Society, Dec. 30, 

 1896. 



