June 10, 1898.] 



SCIENCE. 



807 



numerous new species and subspecies have 

 been described, so that in all respects the new 

 list is very different from its predecessors. 



Looking through the list, from the stand- 

 point of the student of geographical distribu- 

 tion, we notice the following points as worthy 

 of comment : 



1. Notwithstanding our proximity to the 

 Greater Antilles, of which we have an especially 

 lively realization at the present time, we get 

 scarcely more than a tinge of their wonderful 

 snail fauna, even in Florida. Thus the list in- 

 cludes but two Cyclostomatida3, both West In- 

 dian species, and these confined to the hot 

 part of Florida. This seems really remarkable, 

 when we remember the innumerable species of 

 this family in Cuba, and remember, further, 

 that they are operculate and might, therefore, 

 be supposed to resist the sea water and readily 

 travel on floating trees. 



2. The northward distribution of Mexican 

 types is interesting. Bulimulus has kept to the 

 lower levels, as is its wont, but has got as far 

 {B. dealbatus) as North Carolina, Kentucky and 

 Alabama. Holospira, on the other hand, occu- 

 pies mainly the tableland, and even the tops of 

 the mountains in southern New Mexico, but 

 not north of the middle of that Territory. It 

 is a Southern type, extending into the upper 

 Sonoran zone, like the bee-genera Centris, 

 Exomahpsis, etc. 



3. The distribution of our typically Ameri- 

 can snails, Polygyra (sens, lat.), is especially 

 interesting. They are, of course, in great force 

 in the eastern United States, from north to 

 south, and well into Canada. A section of 

 them inhabits the Pacific coast region, and goes 

 inland, like certain slugs of the same region, 

 to northern Idaho. In Wyoming and Colorado 

 the genus is totally lacking, but coming down 

 to New Mexico we find a southern section of 

 it appearing, but only at high elevations. This 

 last-mentioned section extends down to the 

 tableland of Mexico, and even to the lowest 

 levels on the eastern side. It seems possible 

 that Polygyra once inhabited the whole Rocky 

 Mountain region, but that during glacial times 

 was exterminated as far south as the ice went, 

 which must have been about to its present 

 northern limit. It could not well live on the 



low, dry plains, but survived on the moister, 

 forest-clad mountains southward, where it can 

 be found to this day. It may be, therefore, 

 that Polygyra will yet be found fossil in Colo- 

 rado and Wyoming. 



4. In the Limacidse (the ordinary slugs) six 

 species are listed ; but it is not stated, as it 

 should be, that three have been- introduced by 

 man. The remaining three are all very close, 

 indeed, to European forms ; indeed, it has been 

 held on verj^ good authority that Agriolimax 

 campestris is not a species distinct from the 

 European A. Isevis ; while I have more than 

 once examined the Pacific coast Amalia heivstoni 

 both internally and externally, and cannot see 

 that it is anything but A. gagates. Yet there is 

 no doubt that Ag. campestris and Am. hewstoni 

 are native with us ; the former is common al- 

 most all over the country. It is a very striking 

 thing that we should have so few Limacidse, 

 and these so little jjeculiar, when Europe is so 

 rich in large and beautiful types of this family. 



5. The Arionidse, another family of slugs, is 

 well represented in Europe ; but, apart from 

 an introduced species, totally wanting in this 

 country except in the Pacific coast region, ex- 

 tending to northern Idaho, as above mentioned. 

 Here, however, it extends from British Co- 

 lumbia to southern California, and has at least 

 fourteen species, belonging to seven distinct 

 genera, all endemic ! 



Many other interesting facts can be gleaned 

 from a perusal of the list, but it would take too 

 much space to enumerate them. Of adverse 

 criticisms we have few to make, and these re- 

 late to minor points of no general interest. The 

 subfamily Arioninse should not be credited to 

 Pilsbry, as it was indicated and named by W. 

 G. Binney in 1864, and is only now restricted 

 by Pilsbry. The proper citation would be 

 Arioninse (W. G. Binn.) Pilsbry. Veronicella 

 should unquestionably be used in place of Vagi- 

 nulus. Other such matters could be mentioned, 

 but we may leave the subject with the wish 

 that so useful a list might be compiled for many 

 another division of our fauna, at least for the 

 fresh-water mollusca, which have not been cata- 

 logued properly in recent times. 



T. D. A. COCKEEELL. 



Mesilla Park, N. M., May 5, 1898. 



