106 CHAS. L. WALTON. 



The region between Ystwyth and Dyfi appears to be hostile to certain 

 Algce, notably Sdlophora rhizoides, Mesoglcea venniculata, DicUjota dicho- 

 toma and Laurencia hybrida, which are absent from it, and Chondrus 

 crispus and Castagnea virescens, which become more common outside it. 



LIST OF SHORE FAUNA. 



PORIFERA. 



Sycon compressum, Fleming. Low-water mark, in sheltered spots, upon 



Algse, etc. (H. J. F. ; C. L. W.) 

 S. coronatum, Ellis and Sol. Same as last. (C. L. W.) 

 Halisarca dujardini, Johnston. Under surface of stones. (C. L. W.) 

 Halichondria panicea, Pallas. Common in sheltered spots almost 



everywhere. {C. L. W.) 

 Hymeniacidon sanguineum, Grant. Aberystwyth. (C. L. W.) 



CGELENTERATA. 



Podocoryne carnea, M. Sars. Aberystwyth. (C. L. W.) 



Coryne vaginata, Hincks. On Algse in rock-pools or reefs south of 

 Borth. (C.L. W.) 



Zanclea implexa, Alder. One colony, collected by Dr. Salter, 1907. 

 (C. L. W.) 



Obelia dichotoma. On piles of Railway Wharf, Aberdovey, and rock- 

 pools Gwbert-on-Sea. (C. L. W.) 



0. geniculata, Linnaeus. Generally distributed. (H. J. F. ; C. L. W.) 



Sertularia pumila, Linnaeus. Generally distributed ; often abundant on 

 Fucus. (C. L. W.) 



Plumularia echinulata, Lamarck. Aberystwyth. (C. L. W.) 



P. pinnata, Linnseus. General in sheltered pools. (C. L. W.) 



P. similis, Hincks. (H. J. F.) 



Actinia equina, Linnaeus. Generally distributed and locally common. 

 Aberystwyth, Y-Gamlas, Mochras, etc. (C. L. W.) See Journal 

 Marine Biological Association, October, 1911. pp. 228-230. 



Anemonia sulcata, Penn. Generally only a few. Aberystwyth and for 

 a few miles to the south. Tonfunau, etc. (C. L. W.) 



Sagartia miniata, Gosse. One specimen. Aberystwyth. (C. L. W.) 



S. undata, 0. F. Miiller. Observed at Clarach, a little bay to the north 

 of Aberystwyth. Small specimens occur under stones which have 

 become fixed in grooves, on an otherwise very barren erosion plane. 

 Individuals, when kept in captivity, very averse to light. One 

 large specinu'U on reef below the College. (C. L. W.) 



