ZOOLOGY. 
The Fauna of the Mississippi Bottoms. — The Illinois State 
Laboratory of Natural History is engaged in a study of the aquatic 
animals of the state. A contribution to a knowledge of these is given 
by Prof. H. Garman in a recent publication from the laboratory.^ 
When the region was studied the river was high, and hence many forms 
were lacking which might have been found at low water. An astonish- 
ing feature was the great rarity of Batrachia. There was an interesting 
commingling of lake and river fishes in the sloughs. Garman thinks 
some of the Unionidae act as scavengers. Notes are given on the 
various forms of vertebrates and invertebrates collected by the survey, 
but some groups are scarcely touched upon, while forms as prominent 
as the Crustacea are not mentioned in the Report. 
Neomenoidea. — Hansen has had abundant material for the study 
of these interesting molluscs and recognises^ three species of Neomenia 
and six of Proneomenia, P.filiformis being new. Hubrecht's definition 
of the latter genus must be modified, for Hansen finds in two species a 
well developed penis on either side. The same forms show no well 
developed filiform branchiae as in Neomenia, but in the "anal cavity" 
are well developed epithelial folds which are regarded as functional 
gills and the anal cavity of Hubrecht is called a branchial cavity. 
Hansen further describes the various organs in both genera mentioned 
above and also in Chaetoderma. In Proneomenia as in Chaetoderma 
the eggs pass through the pericardium, passing thence by a canal on 
either side into which the vitellaria empty. The blood in the living 
animals is red, but it was not settled whether the color belongs to the 
round or oval nucleated corpuscles or to the serum. 
The Classification of the Lamellibranchs.— Dr. W. H. Dall» 
has attacked this perennial problem from the characters afforded by the 
hinge. In many respects he is in accordance with Neumayr.* In 
short he recognises three types of hinge, although these may intergrade. 
The most archaic, the lack of teeth in the hinge is made to characterize 
1 Preliminary Report on the animals of the waters of the Mississippi Bottoms, near 
Quincy, 111., 1889. 
» Bergens Museums Aarsberetning for 1888 [1889.] 
3 Am. Jour. Set. 6- Arts, XXXVIII.. Dec, 1889. 
* Stz. k. Akad. Wiss, Wien., Math. Nat., CI. I.. Bd. 88. 1883. 
