678 THE AMERICAN NATURALIST. | |Vor. XXXIX. 
The colors of some of the organs, especially of the recep- 
taculum, are striking. This latter organ is colored as follows 
in the different species : — 
appressa, orange. desidiosa, salmon. 
Jugularis, yellowish. mighelsi, pearly white. 
reflexa, yellowish. humilis, salmon. 
emarginata, flesh-colored. auricularia, bright red. 
The receptaculum seminis varies in several of the species, 
both in size and in shape. In palustris it is of extraordinary size 
while in auricularia it is very small. 
While the characters of the genitalia do not seem to aid 
materially in the establishment of higher groups they do aid 
very largely in the separation of the species. The writer hopes 
to be able to examine all of the American species in the near 
future. 
BIBLIOGRAPHY.1 
BAKER, FRANK C. 
The Gross Anatomy of Zimnea emarginata Say, var. mighelsi 
Binney. Bull. Chicago Acad. Sci., vol. 2, pp. 191-211. 
BAUDELOT. 
à Recherches sur l'appareil générateur des mollusques Gastéropode s. 
nn. des Sci. Nat., Zool., ser. 4, vol. 19, pp. 135-222, 268-294. 
KEFERSTEIN, WILHELM. 
'62-— Bronn's Klassen und Ordnungen der Weichthiere; Malacozoa. 
- Leipzig und Heidelberg. : 
LACAZE-DUTHIERS, HENRI. 
'72. Du systeme nerveux des mollusques et d'un nouvel organe d’inner- 
vation. Arch. Zool. Exp., ser. 1, vol. 1, pp. 437-500. 
Moquin-Tanpon, A. ; : JR an 
^ Histoire naturelle des mollusques terrestres et fluviatiles de France. 
Paris, 2 volumes and atlas. 
MoQurN-TANDON, A, 
E. Observations sur les prostates des Gasteropodes androgynes. 
Jour. de Conch., vol. 9, pp. I-19 : 
1 1 2 . * 
The list of works on this subject is not exhaustive. 
