THE NAUTILUS. 69 



Very closely allied genera vary in this respect, as in the case of 

 Arion, Ariolimax, Prophysaou, Anadenus, Anadenulus, etc.; or in 

 the case of Cionella, which has no mucus pore, and Ferussacia, 

 which possesses this gland. It is hardly needful to multiply 

 instances — the Zotntidoi and Helicidce are full of such cases, 

 although many of them are not yet to be found in the conchological 

 text books. The fact seems to be that this caudal gland is simply 

 a local exaggerated development, in a convenient place, of the mucus 

 secreting, glandular structure to be found over nearly the whole 

 upper surface of the foot ; and it is likely to be developed independ- 

 ently in different groups. Its presence in different groups is, in my 

 opinion, no proof of genetic connection. I would therefore retain 

 Charopci, as well as the forms grouping around Gerontki, in the 

 HelicidiB, on account of their dentition, which is not, it seems to 

 me, in any respect Zouitoid.^ 



The connecting links between Charopa, Simplicaria, Pitys, Mao- 

 riana, Endodonta and Libera seem to be too numerous to allow us 

 to regard these as separate genera ; indeed, they are scarcely of 

 subgeneric rank, unless the examination of the animal reveals dif- 

 ferences more fundamental than those now known. 



JAPANESE LIMPETS. 



BY GEO. W. TAYLOR, VICTORIA, B. C. 



The Japanese Patellidie were tabulated by Mr. Pilsbry in the 

 November number of the Nautilus and the table was reproduced 

 with one slight alteration in the Manual of Conchology, vol. 13, p. 

 131, issued a couple of months later. Strangely enough, Mr. 

 Pilsbry omits from his table in both instances one of the commonest 

 species, namely, Helcioniscus encosmius Pilsbry. 



A very fine series of this limpet was sent to me a short time since 

 by the Rev. H. Loomis, of Yokohama, and I have also received it 

 from Japan through Messrs W. H. Harrington and Frederick 

 Stearns. The specimens sent by the last named gentlemen were 



1 Some recent authors speak of the " families" Pattilida, Trochomorphidce' 

 Cochlostylida, etc. It would be well for them to attempt to give a family 

 definition before using such terms. 



