THE NAUTILUS. 89 



larger or smaller part at the anterior end of the gills is not charged, 

 but this may be due to the fact that the contents have been partly 

 discharged. The charged gills are very little swollen, and the em- 

 bryos fill the interstices between the interlaminar connections with- 

 out forming placentas ; yet a slight mutual cohesion of the embryo is 

 present. 



The glochidia are very small. Length, 0.06 mm. ; height, 0.07 

 mm. Their shape is subovato-circular, slightly higher than long. 

 The lower margin is more narrowly rounded, so that a blunt and in- 

 distinct point is indicated. Of the published figures, that of Harms 

 (Zool. Anzeig. 31, 1907, p. 817, fig. 5) comes nearest to the actual 

 shape, but is too regularly round. The other figures of Harms (ibid., 

 fig. 4, and Zool. Jahrb. Anat, 28, 1909, pi. 13, figs. 1 and 2) are 

 poor, since they represented oblique views of the glochidium. The 

 figure of Schierholz (Denkschr. Ak. Wiss. Wien. 55, 1889, pi. 4, fig. 

 65) does not at all represent this species. 



Harms gives 0.0475 mm. as the size, which, according to my 

 measurements, is too small. He also describes and figures small 

 teeth or spines in the middle of the lower margin ; I cannot see 

 these. In their place there is a narrow flange, which projects to- 

 ward the inside of the shell, and in a lateral (edgewise) view, this 

 appears sometimes as a short spine. 



MARGARITANA MARGARITIFERA FALCATA (Gould). (According to 

 Simpson, Pr. U. S. Mus., 22, 1900, p. 677, synonym to M, mar- 

 garitifera) . 



Two specimens from Chehalis River, Porter, Chehalis Co., Wash- 

 ington, collected by H. Hannibal, July, 1912. 



This western form of M. margaritifera, whether we regard it as 

 distinct or not, has exactly the structure of the soft parts of the nor- 

 mal form. In one of the two specimens before me, the arrangement 

 of the interlaminar connections in oblique rows is much more distinct 

 than in the other; the former might possibly be a female. 



FUSCONAJA SUBROTUNDA LEUCOGONA nOV. var. 



This form is the representative of F. subrotunda (Lea) in Elk 

 River in West Virginia (Kanawha drainage). I collected it on May 

 25, 1911, at Sutton, Braxton Co.; on July 8, 1911, at Gassaway, 

 Braxton Co., and July 10, 1911, at Shelton, Clay Co. I also saw 



