14 THE NAUTILUS. 



and extend forward nearly to the middle of the lower margin, 

 becoming quite distaJit and small in front. 



Color of soft parts whitish, with black pigment around anal 

 and branchial openings, and a brown or blackish streak run- 

 ning forward on mantle margin on the insitle of the papillae^ 

 Edge of marsupium with brown pigment. 



This species undoubtedly belongs near the group, of which 

 E. vanuxeniensis may be regarded as the type. The anatomy 

 is practically the same, and the papillae on the mantle margin 

 are very much alike. Also in the shell are certain common 

 peculiarities, since E. venii.sta has, in the female, an indication 

 of that peculiar "constriction" seen in the vanuxemeyisis 

 group. Our species, however, differs in the more elongate 

 shell, weak development of postbasal expansion of the female, 

 which is located rather more anteriorly, thus suggesting, to a 

 degree, the shape seen in Medionidus plateoliis {^=^ conradi) , 

 with which species IJ. plea si has been compared by Marsh. 

 My specimens have a strong tendency to become more or less 

 intensely of a salmon-color in the nacre. 



This seems to be a species characteristic for the Ozark region. 



Lampsilis brevicula (Call). 



L. brevicula and L. brevicida brittsi Simpson, 1900, p. 533. — 



1914, pp. 57, 58. 



L. brittsi Simps, is an absolute synonym of brevicula Call : 

 the differences mentioned by Simpson do not hold good at all. 

 The emargination of the posterior basal margin of the female 

 shell is not always present, probably only in old specimens [aa 

 in L. satura (Lea)]. Among my material there are no speci- 

 mens which show it. 



A number of individuals is at hand from James River, Ga- 

 lena, Stone Co., Mo., and from White River, at Cotter and 

 Norfolk, Baxter Co., Ark. (L. S. Frierson donor). From 

 Galena and Cotter I have specimens with soft parts, collected 

 July 31 and August 2, 1914 (by A. A. Hinkley). Among' 

 them is a gravid female, caught in the act of discharging 

 glochidia (July 31), so that this date indicates the end of the 

 breeding season. 



