Dr. Alex. Brown — On 8olenopora. 



117 



somewliat from the type. The tissue-cells have their walls some- 

 what polygonal, and only feebly sinuous. Cell-division, too, is 

 not observed to be in the same state of activity as exhibited in the 

 ordinary forms. 



i^5i 



Fig. L— Long. sect. SoUnopora compacta, Bill, sp., x 50 d., showing concentric 

 arrangement of cells. 



Solenopora compacta, var. Peaehii, Nich. and Etheridge, jun. 

 Prof. Nicholson has noted that certain specimens obtained from 



Fig. 2. — Tang. sect. Solenopora compacta, Bill, sp., from the Trenton Limestones, 

 X 100 d. Larger cells seen in section are the spore-producing cells (sporangia). 



the Craighead Limestones, Girvan, Ayrshire, possess much wider 

 cells than any other form examined. They are alike, in every 



