310 MEMOIRS OF THE CARNEGIE MUSEUM. 



The sexual differences agree with those of L. ovata ventricosa. 



L. H. D. 



Size: (Males) 1. Shenaiigo, Cat. No. 61.4099 88 mm. 58 mm. 39 mm. 



2. do. " " do 62 " 42 " 29 " 



3. do. " " do 44 " 29 " 18 " 



(Females) 4. Russell, Cat. No. 61.3433 (gravid) 72 " 53 " 35 " 



5. New Galilee, Cat. No. 61.3240 (gravid) 67 " 51 " 34 " 



6. Wurtemberg, Cat. No. 61.4890 (gravid) 47 " 36 " 18 " 



The largest male listed above is the largest individual I have ever seen. 



Soft parts (See Ortmann, 1912, p. 352). Glochidia (See Lea, Obs. VI, 1858, 

 PL 5, fig. 17; Ortmann, /. c; Surber, 1915, p. 1, PL 1, fig. 2). Surber gives the 

 following dimensions: 0.230 X 0.290 mm.; while I gave: 0.25 X 0.29 mm. 



Breeding season: The dates for gravid females are rather complete, extending 

 from Aug. 4 to Oct. 23, and from May 14 to Aug. 9 (the last date furnished dis- 

 charging specimens) . Thus we would have the seasons overlapping early in Aug\ist. 

 The species is clearly bradytictic. (Discharge has been repeatedly observed in 

 July.) 



Remarks: This species is easily recognized and distinguished from L. ovata 

 ventricosa by its small size, regular outline, and the character of the rays. I never 



Fig. 33. 



«. Lampsilis fasciola. 

 m Lampsilis orbiculata. 



had any trouble in identifying it, and I have never seen any tendency to intergrade 

 with ventricosa, and consider it a well-marked species. 



