SUPPLEMENT TO DESCRIPTIONS OF INVERTEBRATES. 



DESCRIPTIONS OF POLYZOA FROM THE PALAEOZOIC ROCKS. 

 By H. A. PROUT, M. D.* 



COSCINIUM WORTHENI, Prout. 



PI. 22, fig. 1. 

 Coscinopora Wortheni, 1860. Proceed. St. Louis Academy of Science, vol. 1, p. 5ft. 



Polyzoum a leaf-like expansion, with a zig-zag midrib, eleva- 

 ted much above the declining sides of the expansion; having 

 lateral branches given out at its salient points, which are like- 

 wise raised above the declining surfaces proceeding from it, 

 and which, as they proceed downward, change at right angles 

 to the original planes of expansion. Dimples long, elliptical ; 

 longitudinal diameter five to seven and a-half ; transverse, one 

 to one-half m. m., oppositely pinnate both on the branches and 

 midrib, about four m. m. apart. Cells large, about four longi- 

 tudinally or transversely in the space of two m. m.; lips round, 



* These descriptions were originally published by Dr. Prout in the Transactions of 

 the St. Louis Academy of Science. Had he lived to revise them for this Report, he 

 would doubtless have modified them in some respects, but as we have not at hand all 

 the specimens before him at the time he drew up the descriptions, we have thought it 

 better to give them as first written by him. M. and W. 



