YEBTEBBATES. 2(55 



Cladodtjs stjccincttjs, St. J. and W. 



PI. 3, Fig. 8-12. 



Associated with the last described teeth, C. Wachsmuthi, is a form 

 almost as numerously represented, which seems to offer persistent pecu- 

 liarities sufficient for its recognition under almost all circumstances. 

 Very similar in form and size to G. Wachsmuthi, they may be chiefly dis- 

 tinguished from that form by the squat outline of the crown viewed in 

 front, stouter median cone, which is marked by strong downward bifur- 

 cating costse which extend nearly, sometimes quite, to the apex, and 

 which are generally nearly equally strongly marked, though more nume- 

 rous, in the posterior face, where they are rarely bifurcated; the outer 

 basal line of the crown is generally occupied by strongly developed 

 accessory processes, especially in the lateral portions, with, however, 

 exceptions in the case of occasional small teeth in which they are 

 absent ; and here are found certain features which go far towards indi- 

 cating the possible specific indentity of these teeth with the form last 

 described, since the present examples present precisely the same basal 

 characters as observed in C. Wachsmuthi, while the coronal costas, 

 excepting the accessory processes, may be found to differ only in the 

 degree of their development. In the normal examples, the outer face 

 of the base is slightly inflected, instead of projecting outward, as is 

 conspicuously the case almost always in the above mentioned form. 



It is not improbable the form here noticed may prove to be merely a 

 variety of C. Wachsmuthi ; but with the present material this is not 

 clearly demonstrable, while on the contrary, its distinguishing peculiar- 

 ities are readily recoguizable on careful examination. 



Geological position and locality : Not uncommon in the upper fish-bed 

 of the Kinderhook division; Burlington, Iowa. 



Cladodus alternatus, St. J. and W. 



PI. 2, Fig. 14-18. 



Teeth below medium size, symmetrical and very graceful in form. 

 Base semi elliptical or trapizoidal in outline, thick, posterior margin 

 broadly rounded in the median region, rapidly so or obliquely truncated 

 lateraliy to the obtusely rounded lateral extremities, anterior border of 

 moderate depth and slightly produced outward, nearly straight or gen- 

 tly depressed in the middle and rounded at the lateral extremities, and 

 produced downward into a rather strong median ridge, which occupies 

 half to two-thirds of the lateral diameter of the base, well-defined later- 



—35 



