A. E. Verrill on the Mollusca of Hurope and N. America. 3 
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 
Leanum, Mactra lateralis, Petricola pholadiformis, P. dactylus, 
Gouldia mactracea, Cytherea convexa, Venus mercenaria, V. no- 
tata, Gemma gemma, Lrocardium Mortoni, Arca transversa, 
Modiola plicatula, Pecten irradians, Ostrea Virginiana, Anomia 
electrica (not of Linn.), Diaphana debilis, Cylichna oryza, Placo- 
branchus catulus, Crepidula fornicata, C. plana, C. convexa, C. 
glauca, lanthina fragilis, Bittium Greenvi, Odostomia bisuturalis, 
O. seminuda, Turbonilla interrupta, Pleurotoma bicarinata, P. pli- 
cata, Nassa obsoleta, Buccinum cinereum, Diacria trispinosa, Lo- 
ligo Peali. : 
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 navalis, T. megotara, T. chlorotica, Solen 
ensis, Machera costata, Pandora trilineata, Lyonsia hyalina, Mac- 
tru solidissima, Kellia planulata, Macoma fusca, Tellina tenera, 
Astarte castanea, A. quadrans, A. sulcata, Nucula proxima, Yoldia 
limatula, Mytilus edulis, Elysia chlorotica, Crucibulum striatum, 
Latiorina rudis, L. tenebrosa, L. palliata, Lunatia heros, L. triseri- 
ata, Nassa trivittata, Melampus bidentatus, 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 of these numerous instances in which he has 
unduly exaggerated our northern fauna, we find not one un- 
doubted instance of an error 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 
this, there are no reasons whatever for most of the special indi- 
cations that he gives. 
Thus he gives the northern distribution to all of the sixteen 
species of Spherium and Pisidium ; but most of them are well 
known to be widely distributed over the eastern, middle, and 
western parts of the United States, some even extending to the 
southern parts. Unio complanatus, U. nasutus, Margaritana 
arcuata, and Anodon implicatus are indicated as distributed 
north of Cape Cod; but all these are found over most of the 
northern and middle states and some in the western, while the 
last one is somewhat rare at the north. But Unio radiatus, U. 
cariosus, U. ochraceus, Margaritana undulata, M, marginata, An- 
