156 KANSAS UNIVERSITY SCIENCE BULLETIN. 



the pedicle valve just in front of the hinge. This specimen was se- 

 lected to be ground, because it was a good specimen, of normal form. 

 Another specimen (No. 3), from the Permian of Cowley county, Kan- 

 sas, has the apices of the spires turned at an angle of about forty-five 

 degrees or more in a vertical direction, causing the point of the spire 

 to be located near the middle of the right side of the brachial valve, 

 while the other points to the opposite of the pedicle valve. The spire 

 is quite flattened, approaching disk shape, with the apex quite ob- 

 tuse and the frontal aperture very narrow and almost slit-like (this 

 may be partially due to a very slight compression, but the compres- 

 sion, if present, is so slight as to modify it very little), owing to the 

 position of the spires in the shell, which prevents their flaring much 

 at the front. The shell is not an old one, and, for this reason, is some- 

 what less ventricose than many adults. The young specimens are 

 much flatter than the old ones in this species. 



The spiralia of No. 10 are turned in a similar manner, but through 

 a much smaller angle. The frontal aperture is typical, as is also the 

 general form of the shell. The spiralia are conical, and the tips prob- 

 ably acute. In No. 6 the position of the spiralia, their form and that 

 of the aperture are normal. Nos. 6 and 9 show spines on the spires 

 The spines are closely set, thick, blunt, and nearly twice as long as 

 broad. In fact, some appear to be nearly as large at the tips as at the 

 base. In No. 9 the spires are normal, except that, instead of being 

 flaring conical, they are more in the shape of a folded shield shape 

 with acute apex. In other words, the frontal aperture is produced by 

 the dorso-ventral compression of the entire cone rather than the flar- 

 ing of the frontal portion. The apex of the left spire is bent somewhat 

 downward. The position of the spiralia in No. 7 is about normal, 

 the tips obtuse, the spires almost perfectly depressed conical, frontal 

 aperture only slightly wider than the space farther back on the side 

 next the brachial valve. No. 5 has apparently been compressed later- 

 ally, through this compression did not affect the positions of the 

 spiralia, for they are normal. They appear to have been of the typical 

 form in every respect. In No. 8 the spires seem to have been 

 turned through a slight vertical angle, though the incompleteness of 

 the specimen prevents a close study of position. The form was ap- 

 parently normal, except that the lower edges may have been somewhat 

 pressed inward. Nos. 1 and 4 are about normal thronghout. No. 2: 

 is normal as far as can be seen, except that the apices are turned 

 through a small vertical angle. The anterior portion of the pedicle 

 valve is crushed in. No. 12 is normal throughout. 



It is unfortunate that none of the specimens show the crural at- 



