264 SMITHSONIAN MISCELLANEOUS COLLECTIONS [vOL. 45 



minute perforation in the corresponding subfusiform swelling of 

 the adnate base. The position of this perforation is generally more 

 nearly central than terminal, and thus corresponds with the facts 

 observed on Rhopalonaria. The only feature in which the known 

 parts fail to correspond is the greater regularity of the development 

 and arrangement of the fusiform swelling of the base in the 

 Rhopalonaria. This surely cannot be of sufficient consequence to 

 deter us from classifying Rhopalonaria as an ancient representation 

 of the MteidcE and more typical Ctenostomata.^ 



The method of growth prevailing in Rhopalonaria is exactly 

 duplicated in D'Orbigny's genus Terehripora,- the known species 

 of which are described and in part figured by Fischer.^ There is, 

 however, a notable difference between the latter genus which con- 

 tains recent species chiefly and the Paleozoic Rhopalonaria, namely, 

 that in Terehripora the cell between the connecting stolons is the 

 zooecium itself with a subterminal orifice bearing a sinus on its lower 

 margin. Terehripora agrees in all essential respects with such Chilos- 

 tomata as Hippothoa, and there can be little doubt that it also is a 

 member of this order. It would be very desirable in the present 

 state of our knowledge that some one should undertake the study 

 of these recent forms in the hope of throwing some light on their 

 possible Paleozoic representatives. 



The delicate thread-like creeping stolons of Vinella and Hetero- 

 nema, new genus, with their median rows of small pores, are, we 

 believe, strictly comparable with the branching stems which support 

 the deciduous zocecia of Vesicularia, a typical Ctenostomatous bryo- 

 zoan. In plate lxv, 4, 5, are reproduced two of Hincks' illustra- 

 tions, somewhat reduced, of V . spinosa Linnseus. Comparing these 

 with Vinella, we observe no dififerences of greater importance than 

 such as might be expected between members of the same order of 

 organisms. Indeed, they are often greater, as in the case of Arach- 

 nidium and V esicularia, a comparison of whose zoaria constantly 

 brings out more distinctions than can be made out between those 

 of Vesicidaria and Vinella. The point that is deemed the most 

 significant in the comparison is the row of pores on the branching 

 stem in the one case and the creeping stolons in the other, which in 

 the case of Vesicularia do, and in Vinella are believed to, mark the 



^ Hincks {British Marine Polysoa) arranges ^tea with the Chilostomata, 

 but admits the Ctenostomatous affinities of the genus. In our opinion the 

 latter predominate decidedly over the former. 



^ Voyage dans I'Amerique Merid., t. vi, 1839, p. 23, pi. x. 



" Nouv. Arch. Mus. Hist. Nat., u, 1866, pp. 293-313, pi. xi. 



