166 THE NAIADES OF MISSOURI 



for this State the writer finds the supra-anal opening present. 

 Its presence has been doubted by some other writers. This pygmied 

 mussel has great vitality. The writer records thirty-eight heart 

 beats per minute — among the most rapid of the Naiades. It is 

 one of the most active in its locomotion. Its breeding season show 

 it to be bradytictic. The writer has been fortunate to secure parva's 

 glochidiuyn and make more of a definite study than has been recorded 

 since Lea left his sttidies. (Obs. XIII, 1874, pi. XXI, fig. 2.) 



Carunculina texasensis (Lea). 



("Texas Shell.") 



Not figured. 



1857 — Unio texasensis Lea, Pr. Ac. Nat. Sci. Phila., p. 84; Jl. Ac. 

 N. Sci., IV, i860, p. 359, pl. XLI, fig. 184. 



1862 — Unio bealei Lea, Jl. Ac. N. Sci., V., p. 204, pl. XXX, fig. 273. 



1912b — Eurynia (Carunculina) texasensis Ortmann, An. Car. Mus., 

 VIII, p. 339- 



Animal Characters: — The writer not having seen the 

 soft parts of this species quotes Simpson's description: — "Animal 

 with marsupium consisting of a few large ovisacs (8 to 13); inner 

 gills wholly, or in part, free from the abdominal sac; female 

 often having a well developed caruncle on the mantle below the 

 branchial opening." 



shell characters. 



External Structures: — Shell small, rather thick, subin- 

 flated, smooth, rounded before, pointed post-dorsad; post- 

 umbonal fidge rather prominent, especially in the female shell, 

 which is shorter, more inflated and not so pointed posteriorly; 

 epidermis a dark slaty color with one or two whitish rest lines; 

 beaks low with coarse concentric bars upcurved at base of post- 

 ridge. 



Internal Structures: — Cardinals double in right, faintly 

 so in left valve; laterals single in both; interdentum lacking; 

 beak and branchial cavities rather shallow and irridescent pos- 

 teriorly. 



Sex Length Height Diameter Locality 



cf 45 X 24 X 1 7. 5, mm (Lost Creek, Amity) 

 9 37 X 20 X 1 2.0mm (Lost Creek, Amity) 



Miscellaneous Remarks: — Comparison to some types of 

 texasensis from Wimberly Lake, Texas, assures the writer that 



