292 Geological Society. 



Isastrcm oblonga, Edw. & H., was correctly described by those 

 authors, and no addition to our knowledge of the form, has been 

 made. The genus Isastrcm has its species budding within the calice 

 and close to the outer wall, never, as stated, between the walls of 

 calicos. Heliocoenia is a subgenus of Stylina, and differs from Placo- 

 coenia, d'Orb. Isastrcea Conyhearn, Edw. & H., is a good species ; 

 it is not the same as Clausastrcea:=Plerastra'a Pratti, Edw. & EL. 

 The type specimen of Plerastra'ci Pratti., Edw. & H., has a columella, 

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

 tial columella. BatJu/aenia, Tomes : nothing was stated in the work 

 called 'A Revision of the Genera of Madreporaria ' about the simi- 

 larity of this genus and StylosmUia ; this is a statement difficult of 

 explanation. 



Every one of these numerous statements is made in opposition to 

 the opinions of Mr. Tomes. Proper acknowledgment is made 

 regarding the useful knowledge conveyed by Mr. Tomes about the 

 localities of corals and the zones which 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- 

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

 Dimorpliastrcpa diihia, and that properly the generic name should be 

 Dlmorpharcea. Again, Mr. Tomes has raised much doubt in the 

 author's mind where a species placed by him under the genus Lepi- 

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

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

 requires careful working out. 



3. " On the Astroccenia; of the Sutton Stone of the Infra-Lias of 

 South Wales." By Prof. P. Martin Duncan, M.B., E.Pt.S., E.G.S. 



The species which were placed in the genus Astroccenia, and 

 which came from the Sutton Stone and Brocastle deposits of the 

 Infra-Lias of South Wales, were reexamined 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. p>arasitica^ and the 

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

 any iutermural structure or ccenenchyma in that sense. 



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

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



Is^vemberlS, 1885.— Prof. T. G. Bonney, D.Sc, LL.D., F.R.S., 



President, in the Chair. 

 The following communications were read : — 

 1. "Results of Recent Researches in some Bone-caves in North 

 Wales (Fynnon Beuno and Cae Gwyn)." By Henry Hicks, M.D,, 



