﻿4§ SMITHSONIAN MISCELLANEOUS COLLECTIONS [VOL. 47 



dant at a number of localities in the states mentioned above. C. 

 parva, described below, occurred in considerable numbers in Ten- 

 nessee and several additional new species are known to us from the 

 Trenton rocks of Kentucky. 



CALLOPORINA PARVA new species 

 ( Plate XIV, 13-16) 



Zoarium small, ramose or subramose ; branches cylindrical or com- 

 pressed, 2 to 4 mm. wide, arising from an expanded base and not 

 reaching- a height of more than 20 or 30 mm. Surface smooth with 

 inconspicuous macula?. Zocecial apertures angular, 9 to 10 in 2 mm. 

 Mesopores small and rather few in number. 



Vertical fractures show the crenulated walls and iridescence 

 spoken of under the discussion of the genus. Thin sections show 

 that the number of crenulations in a given space varies somewhat, 

 but 16 in 2 mm. is a fair average. Diaphragms are as required for 

 the genus, wanting in both zocecia and mesopores. 



Although agreeing in all essential internal characters with Cal- 

 loporina crenulata (see plate xrv, 17-19), this species is readily dis- 

 tinguished. C. crenulata forms large, bushy masses, composed of 

 strong, monticulated branches, with rounded zocecia (8 in 2 mm.) 

 and numerous small mesopores. C. parva, on the other hand, has a 

 few narrow, smooth branches, containing smaller zocecia and fewer 

 mesopores. 



Occurrence. — Abundant in a thin shaly bed of the age of the Black 

 River formation, 2 miles south of Belfast, Marshall county, Ten- 

 nessee. 



Cat. Xo. 43,217, U. S. X. M. 



Family TREMATOPORIDJE Ulrich 



\\ e have paid some attention to the characters separating this 

 family from the CaUoporidoc, but as our investigations have not been 

 completed, it is deemed unwise to express ourselves definitely at the 

 present opportunity. We may say, however, that so far as we have 

 gone, the published reasons for maintaining the Trematoporidcs 

 have not been impaired. There are differences, when compared with 

 Calloporidce — in the development of the zocecia, in the mesopores, 

 and in the acanthopores — that require some recognition, and as now 

 constituted there is little difficulty in separating the two families. 

 \t some future time we shall publish a new genus, represented by 

 several species in the formations of the Stones River group in Ten- 

 nessee, that may he succinctly described as a group of acanthopored 



