ORTMANN: monograph of the naiades of PENNSYLVANIA. 



269 



L. H. 



Size: 1. West Springfield, Cat. No. 61.4091 (cT) 65 mm. 35 mm. 



2. do. " " do. (9) 51 



3. do. " " do. id') 48 



4. do. " " do. (9 gra\'id) . .44 



5. Erie, Cat. No. 61.4832 (cf ) 56 



6. do. Cat. No. 61.4831 ( 9 ) 56 



7. do. Cat. No. 61.4833 (cf ) 54 



8. do. Cat. No. 61.4093 ( 9 ) 45 



29 

 28 

 24 

 32 

 29 

 28 

 25 



D. 



23 mm. 



18 



17 



13 



21 



20 



17 



16 



Soft parts identical with those of typical E. iris (See Ortmarm, 1912, p. 341). 

 Glochidia (See Lea, Obs. VI, 1858, PL 5, fig. 14; Ortmann, 19116, PL 89, fig. 20 

 as of E. iris) . 



Breeding season: May 23, 1909, is the only date, at which I found gravid 

 females. Thej^ all had glochidia. 



Remarks: The color-pattern is the chief diagnostic character of this form. 

 In addition the grovmd-color of the epidermis is generally lighter than in the typical 

 E. iris, but this is not constant. The lake-form differs from that of Conneaut 

 Creek by often (but not always) having the epidermis chestnut-brown especially 

 toward the beaks. 



Intergi-ades seem to be present. Baker (1898a) mentioned that the color 

 varies in the Chicago area, and I have transitional specimens from Winona Lake. 

 Even in Lea's types the typical color-pattern is not very well developed. 



It should be mentioned, that in shells from the Cumberland and Tennessee 

 drainages belonging to this tji^e, the broken and spotted rays turn up frequently. 

 This will be discussed elsewhere. The geographical relations of these forms which 

 are generally referred to E. nehulosa Conrad, are stiU obscure. 



Localities in Pennsylvania represented in the Carnegie Museum: 



Lake Erie, Presque Isle Bay, Erie, Erie Co. 

 Conneaut Creek, West Springfield, Erie Co. 



Other localities represented in the Carnegie Museum. 



Mohawk River, New York (Smith collection). 



Genesee River, Rochester, Monroe Co., New York (R. H. Santens). 



Black Creek, Cliili, Monroe Co., New York (R. H. Santens). 



Lake Erie, Port Rowan, Norfolk Co., Ontario, Canada (C. Goodrich). 



Grand River, Cayuga, Haldimand Co., Ontario, Canada (C. Goodrich). 



Sandusky River, Upper Sandusky, Wyandot Co., Ohio (C. Goodrich). 



Swan Creek, Toledo, Lucas Co., Ohio (C. Goodrich). 



Raisin River, Grape P. 0., Monroe Co.; Adrian and Tecumseh, Lenawee Co., Michigan (C. Goodrich). 



Winona Lake, Kosciusko Co., Indiana (E. B. Williamson). 



Sheyenne River, Argusville, Cass Co., North Dakota (S. M. Edwards). 



