PALEONTOLOGIC CONTRIBUTIONS 25 



appears possible that they were divided into many small air 

 chambers as in Porpita, these lines being the chamber walls. These 

 concentric chamber walls would seem to have been lacking in the 

 first cycle from the appearance of the cast of the first cycle in the 

 smaller specimen, yet the same specimen shows on the compressed 



Fig. 10 P o r p i t a sp. Young specimen, with the 

 eight primary chambers, (x 44). Recent, coast of 

 Florida. Copy from Alexander Agassiz 



lower side (in the figure) the concentric lines also over this region. 

 On the other hand, it is quite apparent from a comparison of the 

 early growth-stages of Porpita, figured by Agassiz (op. cit., pi. 9, 

 1—4 ; see also text fig. 10) with Paropsonema crypt ophya 

 that they, with their first cycle of club-shaped chambers and the 

 two to three cycles of successive chambers, each set of which is 

 alternating with the preceding, give a picture entirely alike to that 

 of Paropsonema, with the exception of the concentric rows of 

 pores upon the chambers of the latter. The larger specimen shows 

 a distinctly outlined small circle, about 4 mm in diameter in the 

 center, from which fine lines radiate. This may correspond to the 

 central spheroidal chamber of the float of Porpita. 



A further specimen brought into the Museum since the former 

 publication is rolled up like a withered leaf- or the cover of a cigar. 

 Also the smaller specimen, here figured, is partly infolded from the 

 edges, and Doctor Clarke has also figured several specimens in this 



