284 



MEMOIRS OF THE CARNEGIE MUSEUM. 



L. 



Size: (Males) 1. Linesville, Cat. No. 61.4027 142 mm. 



2. Jamestown, Cat. No. 61.3453 . . . .' 125 " 



3. Rosston, Cat. No. 61.4036 78 " 



(Females) 4. Linesville, Cat. No. 61.4027 (gravid) . . Ill " 



5. Wampum, Cat. No. 61.2873 101 " 



6. Shenango, Cat. No. 61.4100 (gravid) . . 71 " 



The maximum length given by Baker (1898o) is 116 mm., by Scammon 

 (1906), 136 mm. Thus it is seen that the Pennsylvanian specimens attain an 

 extreme size. 



Soft parts (See Ortmann, 1912, p. 348). Glochidia (See Lea, Obs. VI, 1856, 

 PI. 5, fig. 10; Surber, 1912, PI. 2, fig. 15). My measurements are: 0.23 X 0.28, 

 while Surber gives: 0.250 X 0.290 mm. But Surber remarks (1912, p. 4) that 

 at certain localities, the glochidia are uniformly smaller than at others. 



Breeding season: My dates for gravid females are very numerous, and cover 

 the periods from August 3 to October 27, and from April 22 to July 19. The 



Fig. 30. 

 • Lampsilis luteola. 

 ■ Do. var. rosacea. 



species is hradytictic, but found gravid nearly all the year round, except in July, 

 where there seems to be a short interim. Although gravid (and discharging) 

 females have been found in July, they are rare in this condition in that month. 



Remarks: A very variable species, but recognized by its subelongated shape, 

 the light color of the epidermis, which is shining, and has generally weU-marked 



