ROGERS: SOME NEW AMERICAN SPECIES OF CYCLUS. 271 



is smooth, and the granulations are more prominent than in C.jonesi- 

 anus. 



C. communis is much more abundant than the other species here 

 described, though good specimens are rare. About eighty speci- 

 mens, most of them very imperfect, were obtained from the Iola 

 limestone, whereas from only one to three specimens of the other 

 species were obtained. Some of the specimens are quite small and 

 not nearly so tumid as the types. These may possibly represent 

 another species, but it is more probable that they are young or stunted 

 forms. 



Cyclus packardi, n. sp. Plate XIV, figs. 2, 2a. 



Carapace rather flat, decidedly shield like, transversely subellip- 

 tical in outline. The edge of the carapace is concealed by the matrix, 

 so that it cannot be said whether or not a margin is present. A well- 

 defined median ridge reaches from the posterior border to the center 

 of the carapace, where it expands into a small subcircular promi- 

 nence, with a slight horizontal carina. Directly in front of the expan- 

 sion is a quinquelobate prominence, consisting of a median anterior 

 lobe and two paired posterior ones. Of these lobes, the middle or an- 

 terior paired ones are the largest and project laterally over the others. 

 The posterior pair are occupied with several transverse ribs. Arising 

 on each side of the median ridge, near its middle, is a ridge extend- 

 ing toward the an tero- lateral border, where it expands to form a promi- 

 nent oval-shaped lobe. Distad of this last-mentioned ridge and sep- 

 arated from it by a narrow furrow is a sharp, narrow ridge also 

 extending antero-laterally, but after a short distance it curves for- 

 ward, crossing the other ridge, and then expands to form a subtriangu- 

 lar lobe, which is but a short distance from the lateral surface of the 

 quinquelobate prominence. These ridges are the "inner fork" and 

 "outer fork" of Reed.* 



The more elevated parts of the carapace, with the exception of the 

 quinquelobate prominence and the median ridge, are covered with 

 small tubercles which are sometimes rather prominent. 



Measurement. Largest specimen. Smallest specimen. 



Length 7o+ mm 5£ mm. 



Breadth. 11 mm 8 mm. 



Height (cannot be determined.) 



Position and locality: Upper Coal Measures, Iola limestone, 

 Kansas City, Mo. Three specimens. 



C. packardi does not resemble any other described species of the 

 genus. In the disposition of the "inner" and "outer forks" it is a 



*Geol. Mag., vol. X, p. 61, 1&93. 



