572 Correspondence — Prof. E. D, Cope. 



it is not the same as Clausastrma = Flerastrcea Pratti, Edw. & H. 

 The type specimen of Plerastrcea Pratti, Edw. & H., has a columella, 

 and the authors of the genus did not describe it as having an 

 essential columella. Bathycoenia, Tomes : nothing was stated in the 

 work called " A Revision of the Genera of Madreporaria " about the 

 similarity of this genus and Stylosmilia ; this is a statement difficult 

 of explanation. 



Every one of these numerous statements is made in opposition to 

 the opinions of Mr. Tomes. Pi'oper acknowledgment is made 

 regarding the useful knowledge conveyed by Mr. Tomes about the 

 localities of corals and the zones w^hich some frequent. 



The author of this communication agrees with Mr. Tomes on two 

 points : Mr. Tomes has shown that, owing to the matrix of Cyclo- 

 lijtes Lycetti, Dune, not being sufficiently removed, the form is his 

 DimorphastrcBa dubia, and that properly the generic name should be 

 Dimorphar(sa. Again, Mr. Tomes has raised much doubt in the 

 author's mind where a species is placed by him under the genus Zep^- 

 dophylUa, Dune, should be placed ; probably it will have to come 

 within Donacosmilia, as stated by Mr. Tomes ; but Bonacosmilia 

 requires careful working out. 



3. " On the Astrocoenice of the Sutton Stone of the Infra-Lias of 

 South Wales." By Prof. P. Martin Duncan, M.B., F.RS., F.G.S. 



The species which were placed in the genus Astrocoenia, and 

 which came from the Sutton Stone and Brocastle deposits of the 

 Infra-Lias of South Wales, were re-examined in the instance of 

 A. gihhosa, A. insignis, A. parasitica, and A. plana (Dune). These 

 species were originally described by the author in his ' Monograph 

 of the British Fossil Corals,' second series, Pal. Soc. 1867, pt. iv. 

 No. 1, and were illustrated. A good specimen of A. gihhosa is de- 

 scribed, and its structures are shown to be strictly Astrocoenian. 

 The different states of the corallites produced by various conditions, 

 such as growth and gemmation, were explained. The same course 

 was taken with reference to A. insignis and A. parasitica, and the 

 density of the united walls was shown to have nothing to do with 

 any intermural structure or coenenchyma in that sense. 



A. plana was critically examined, and as it has all the characters 

 of typical Astroccenice, it remains in that genus with the others. 



co:RJEi:Eis:E>oisrjD:Hiisrc:Ei. 



PALiEONTOLOGICAL NOMENCLATUEE. 

 Sir, — With your permission I wish to present some remarks on 

 the review of certain of my papers which Mr. Lydekker published 

 in the number of the Geological Magazine for October, 1885. 

 The author of the review in question does me the honour to agree 

 with me in my determinations of affinities, but he expresses general 

 disapproval of my systematic methods. While I am much gratified 

 at the agreement in more important matters thus expressed or im- 

 plied, I think it very desirable that there should be a harmony of 



