MOLLUSCA. 
231 
. Fifty species, those from Greenland and Mexico included. 
Two are identified with European species : L. st agnails (L.) 
— appressa Bx\di jugularis (Say) and palustris (Mull.)=/r«- 
gilis (Haldeman), both occurring in the Atlantic, Middle, and 
Pacific States of the Union. 
Lea, F. Descriptions of twenty-four new species of Physa of 
the United States and Canada. Proc. Acad* Nat. Sc. 
Philadelphia, 1864, April, pp. 114-116. 
Tryon, G. W. Catalogue of the species of Physa inhabiting 
the United States. Am. Journ. Conch, i. pp. 165-173. 
Sixty species. 
(Melanidte = StREPOMATII)A5.) 
Tryon, G . W. Observations on the family of Strepomatid(je, 
Am. Journ. Conch, ii. pp. 97-135. 
Four hundred and sixty-four species, all North- American. 
About two-thirds are inhabitants of the upper Tennessee river 
and its branches in East Tennessee and North Alabama, and of 
the Coosa river in the latter State, “ the great centre of Hhis 
kind of animal life.^^ Very few species have been found so far 
north as the Ohio river, and they are nowhere numerous 
within a humbed iniles of the sea-coast. The species of tlic 
North Atlantic States, the very few forms of the great northern 
lakes, and the species of the Pacific States belong all to the 
Goniohasic section, which occupies also the entire southern 
country, with one or two species in Mexico and Cuba. The 
Trypanostomoid section is much more restricted, being confined 
principally to the streams tributaiy to the Mississippi and the 
Gulf of Mexico : the Mississippi appears to form the western 
boundary. The Trypanostommd forms attain their maximum 
development in size and number in the Tennessee river, the 
Goniohasic forms in the Coosa river : the most striking genus 
of the former, /o, inhabits the Tennessee only, ' Schizostoma 
the Coosa river only ; and neither of them is found elsewhere. 
One species only, Goniobasis sordida (Lea), is common to 
both sides of the Mississippi. No species inhabits the New 
England States; those of the great lakes, few in number and 
small in size, but very numerous in individuals, fade out as 
completely on approaching the Ohio as do the southern species, 
a fact which favours the theory of a separate creation. 
An abstract on the systematic contents will be given subse- 
quently, in the special part. 
Anthony, J. G. Descriptions of two new species of Goniobasis^ 
Am. Journ. Conch, i. p. 36, pi. 1. figs. 1-3. 
