208 Prof. A. E. Verrill on the Mollusca 



But the special errors to wliicli I wish to call attention occur 

 in the table of species, showing their geographical distribution. 

 These relate both to the names and specific identity of certain 

 shells, and to the geographical distribution. Although not 

 agreeing with the author in regard to many of his remarks con- 

 cerning the generic relations and names of species, I do not 

 propose to discuss them here ; for there seems to be no danger 

 of their general adoption either in Europe or America. 



The following marine species (named as in Gould) which 

 Mr. Jeffreys puts down as belonging to the region north of 

 Cape Cod, actually belong properly to the region south of 

 Cape Cod, extending in most cases to the Carolina coasts or 

 beyond, while north of Cape Cod they are rare or local, viz.: — 

 Cochlodesma Leanuvij Mactra lateralia^ PetricoJa jyholadiformisj 

 P. dactyluSj Goiddia mactracea^ Cytherea convexa, Venus 

 mercenarta, V. notata, Gemma qemtna, Liocardium Mortow\ 

 Area transversa^ Modiola plicatula, Pecten irradians^ Ostrea 

 virginiana^ Anomia eleetrica (not of Linn.), Diaphana debilis^ 

 Cylichna oryza, Placohranchus catuhis, Crejndida Jbrmcata, 

 C. j)lana, C. convexa, C. glauca, lanthina fragilis^ Bittium 

 Greenii^ Odostomia bisuturalis, 0. seminuda^ TurhoniUa tn- 

 terriqjta^ Pleurotoma hicarinata, P. plicata^ Nassa obsoleta, 

 Buccinum cinereum^ Diacria trisjnnosaj Loligo Pealii. 



The following, to which a northern distribution is likewise 

 given, are also found far south of Cape Cod, and many of them 

 belong quite as much to the southern as to the northern division ; 

 and some of them are decidedly southern, extending even to the 

 Gulf of Mexico : — Teredo navali's, T. megotara^ T. cMorotica, 

 Solen ensisj Machcera costata, Pandora trtlineata, Lyonsia 

 hyalina^ Mactra solidissima, Kellia planidata^ Macoma fusca^ 

 Tellina tenera, Astarte casfaneaj A. quadrans, A. sulcata, 

 Nucula proxima, Yoldia limatula, Mytilus edulis, Elysia chlo- 

 rotica, Crucihulum striatum, Littorina rudis, L. tenebrosa, 

 L. palliata, Lunatia heros, L. triseriata, Nassa trivittata, 

 Melampushidentatus, Alexia myosotis. 



Many others, not named in the above lists, are not limited 

 by Cape Cod ; but as they belong properly to the northern 

 division, they are here omitted. 



As an offset to these numerous instances in which he has 

 unduly exaggerated our northern fauna, we find not one un- 

 doubted instance of an eiTor on the other side, among the 

 marine shells. 



The distribution indicated for our land and freshwater shells 

 is even more erroneous. It is sufficiently evident that Cape 

 Cod is in no sense a proper boundary between the northern and 

 southern fluviatile and terrestrial species ; but, disregarding 



