516 Notices of Memoirs — G. R. Vine on Fossil Poh/zoa. 



in some of the beds of the Hamilton Formation. It is allied to 

 C. punctata, Gold., and Millepora interporosa, Phill. (Geol. of York). 

 I am at present unable to decide as to its true generic affinities, and 

 have simply referred it provisionally to Ceriopora." I will also leave 

 it and the other species alone for the present. The whole of the 

 Cerioporidce will have to be revised, and species from the Silurian 

 to the Crag will have to be re-worked. 



1821. Spiropora, Lamx. 

 In some of the shale- washings supplied to me by Mr. Maw from 

 strata below the Wenlock Limestone, I have come across many 

 beautiful fragments of this genus, which will enable me to carry 

 back the type to Silurian times. Mr. Ealfe Tate has already carried 

 back the genus to the Lias,^ but the specific differences between the 

 Liassic and Siluilan forms are very marked. The Silurian species I 

 shall describe under the name of Spiropora regularis, Vine. 



1874. Botrijllopora, Nicholson.^ 



This curious genus, founded by Nicholson for Devonian species, is 

 allied to Defrancia and Lichenopora, but unlike either. The author 

 says, "I have been unable to refer these singular Polyzoa to any 

 existing group, and have therefore been compelled to found a new 

 genus for their reception. Zoarium calcareous, sessile, and encrust- 

 ing, forming systems of small circular discs, the upper surfaces of 

 which are marked with radiating ridges, upon which the cells are 

 carried. Each disc is attached by its entire lower surface, slightly 

 convex above, with a central nonporiferous space, round which a 

 number of radiating poriferous ridges occupy an exterior, slightly 

 elevated zone. Cells forming a double series on each ridge, immersed 

 with rounded mouths, which are not elevated in any part of their 

 circumference above the general surface." ^ 



One species is given, B. socialis, Nich. pi. ix. fig. 16, and it is not 

 of very rare occurrence in the Hamilton Formation. I have not seen 

 among any of our own Palaeozoic Polyzoa any approach to this 

 genus. It may be well to direct attention to the characters, because 

 workers may find even this amongst the group of our hitherto most 

 neglected fossils. 



In my first Eeport ("British Carboniferous Polyzoa," 1880'') I 

 said that " to the Paleontologist the study of the Palaeozoic Polyzoa 

 opens up many very important biological details ; for the connexion 

 of the Polyzoa with the Graptolites is a question that must be dealt 

 with in detail." 



Since this was written I have gone over much that has been 

 written in this country on this debatable subject. Professor Huxley, 

 Mr. Salter, and Professor H. Alley ne Nicholson have severally occu- 

 pied themselves with this question of affinity. Mr. Salter says, " I 

 think Professor Huxley first suggested the resemblance to Defran- 



^ Spiropora liassica, Tate, Geol. Mag. 1875. 



" Canadian Joiirn. No. 80 ; Geol. Mag. 1874, p. 23. » jn^, p. 23. 



■* British Association Eeports. 



