Lower Helderberg Fauna. 307 



indiscriminately placed without being disposed in vertical series. 

 The projection of the outer wall, which gives to C. Clarlcei a 

 labiate appearance, is not a well-marked character in this species. 



Horizon. — Shaly limestone at a slightly higher level than C, 

 Clarhie. 



Locality. — Clarksville, K. Y. 



Vermipora, Hall, 1874. 



This genus has been usually regarded as a coral, closely allied 

 to AuLOPORA, a sort of vertical aggregation of Aulopora tubes. 

 Such a classification, however, overlooks several important struc- 

 tural characters, which, if duly considered, would place it among 

 the Bryozoa, in close proximity to Hederella. 



The genus Aulopora, Goldfuss,'^is said to have neither tabulae 

 nor septa,t although most species are found to possess them. 

 Hall states that the type species of Yermipora is without both 

 septa and tabulae, and my own observations confirm the statement. 

 In this particular and also in its system of budding Yermipora 

 agrees with Hederella. In the latter genus there is a central 

 stolonal rhachis, which sends off buds pinnately. The stolon is 

 often very long, and the buds may also reach a considerable 

 length in some species. In Aulopora the system is quite dif- 

 ferent. There is no long central axis, but each ceU grows for a 

 short distance in the line of such axis, then bending upward, puts 

 forth one or two buds, which in turn repeat the same process. 

 Each corallite ceases to grow shortly after budding and the 

 rhachis, instead of being simple and homogeneous, is composite. 



Therefore it seems advisable to remove Yermipora from its 

 position near Aulopora, and as it possesses points of resemblance 

 to Hederella, I have associated it with that genus. There is, 

 however, another form, Clonopora, closely allied to Hederella, 

 but differing from Yermipora chiefly in that the buds bend out- 

 ward from the stem in umbels. It may be a synonym for the 

 latter, and at all events is closely related to it. * 



* GOLDFTSS, 1826. Petrlf . Ger., vol. I, p. 82. 



+ Hall, 1887. Pal. New York, vol. VI, pp. xn and 5. 



