[Proc. Rot. Soc. Victoria, 31 (N.S.), Part I[., 1919]. 



Art. XVII. — Neiv or Little-known Victorian Fossils in the 

 National Maseuni. 



Part XXTII. — On some Hydroid Remains of Lower Palaeozoic? 

 Age from Monegktta, near Lancefield. 



By FREDERICK CHAPMAN, A.L.S., &c. 



(Palaeontologist, National Museum, Melbourne). 



(With Plates XIX. and XX.). 

 [Kead 12th December, 1918]. 



Introductory Note. 



So far as I am aware no fossils which can be referred to the- 

 Hydroid Coelenterates of the Order Cali/pfoblastea, other than the- 

 Dendrograptidae, have yet been recorded, with some possible excep- 

 tions in the Pleistocene. It m rather puzzling to note this fact, 

 seeing how abundant the '* Sea-firs " (Sertulariidae), the Plumu- 

 larias and the Campanularias are at the present day. And this i» 

 especially so when we take into account the chitinous structure of 

 the hydrosome. 



Some forms, however, wliich have been figured by Ruedemann^ 

 under the generic names Cho^magraptua and Mastigograptns, 

 closely approach the presenti specimens; in fact, one of our speciesr- 

 seems referable to the latter genus. 



On account of many points of resemblance with hydroids of the- 

 Campanularid type, tlie presently described fossils are referred 

 with little hesitation to this group. Thus the Victorian specimens, 

 show an absence of bilateral or radial synimetry which is a dis- 

 tinctive character of the Graptolites, tlie hydrosome is more irregu^ 

 larly flexuose pointing to a rooted liabit, and there is undoubted' 

 evidence of gonothecae attached to the hydrosome. 



It is only right to mention here that Ruedemann himself, in' 

 discussing the general affinities of the graptolites with modern 

 hydrozoa says, in regard to the conical thecae of some of these 

 forms noAv under notice'-': — '* It can be said that this type of 

 thecae would be more similar to the thecae of the hydrozoans**' [sic- 



1 Kep. N.Y. State Mas., Mem. No. II, 1908. iruedeniann.— "The Gmptolites of New York, 

 pt. ii., pp. 210-228, pis. ix.-xii. 



2 Op. cit., p. 213. 



