491 
sys LEMATIC.CATALOG OP THE MOLLUSCA. 
Ciass-PELECY PODA. 
OrDER PRIONODESMACEA. 
Superfamily NAIADACEA. 
Family UNIONIDA. 
Genus Lampsi Lis Rafinesque. 
Lampsilis parva (Barnes). Moll. Chi. Area, Pl. XIII, Fig. 3, 
Station XXII. 
Genus ANoDoNTA (Bruguiére) Lamarck. 
Anodonta grandis Say. Moll. Chi. Area, Pl. II. 
Station XXI. The shells of grandis are unusually thick and solid 
and of a rich greenish-brown color. 
Genus ANODONTOIDES Simpson. 
Anodontoides ferussacianus (Lea). Moll. Chi. Area, Pl. V, Fig. 2. 
Station X XI. 
OrDER TELEODESMACEA. 
Superfamily CYRENACEA. 
Family SPHARIIDA. 
Genus SPH2RIUM Scopoli. 
Spherium stamineum Conrad. Moll. Chi. Area, Pl. XXVII, Fig. 1. 
Station X XI. 
Spherium occidentale Prime. Moll. Chi. Area, Pl. XXVII, Fig. 10. 
Stanions PV) Ie xi XI. XV, SVE, XVII. XIX. ° Occidentale 
is almost always, at least in the area under consideration, an inhabit- 
ant of transient pools and ditches. 
Genus Muscutium Link. 
Musculium partumeivum (Say). Moll. Chi. Area, Pl. XXVII, Fig. 6. 
etations: I) ITT. Vily ix, XI) XVI XXXII The young of 
partumetum somewhat resemble immature Musculium truncatum. 
This species (partumeium) is quite characteristic of the summer-dry 
pools of northern Illinois. 
Musculium transversum (Linsley). Moll. Chi. Area, Pl. XXVII, Fig. 5. 
Station XXI. Transversum is characteristic of the rivers, which do 
not entirely dry up in the summer. It is never found, in this area 
in the summer-dry ponds. 
