BAILY ON MARINE INVERTEBRATA AT PORTMARNOCK. 253 



as small Serpulse, Spirorbis, and Cellepora. Its habitat, according 

 to Dr. Johnston, is on shells and rocks near low water mark, also in 

 deep water. 



ACALEPHA. 



Rhizostoma Cuvieri ? — A species common to the European seas. This 

 is, I believe, the correct designation for the Jelly Fish, some hundreds of 

 which of various sizes were strewn upon the beach on the morning of 

 my visit. The disk or umbrella measured from one to two feet in diameter, 

 and was surrounded with lobes or festoons forming a band of a beautiful 

 purple colour. 



HELIANTHOIDA. 



Actinia mesemlryanthemum. — This well-known species of Sea Ane- 

 mone is rather abundant between tidemarks on the limestone rocks, 

 near the Martello Tower. 



POLYZOA INFUNDIBULATA. 



Tululipora pnalangea ? — An incrusting polyzoon upon rocks, shells, 

 seaweeds, &c. I have some little hesitation in referring the specimens 

 collected to this species ; they are attached to a pebble, and the shell of 

 Fusus aniiquits. 



Crisidia cornuta, Goats' Horn Coralline. — This pretty little spe- 

 cies, which is very abundant on this and other parts of the British 

 coast, is parasitic, occurring in small white bunches on the Sickle Co- 

 ralline. 



Crisia elurnea, Tufted Ivory Coralline — Is another small parasitic 

 species, also very abundant upon seaweeds, shells, &c. I found what 

 I consider to be this species growing in bunches upon Alcyonium digi- 

 tatum. 



Cellepora pumicom. — Occurs frequently in small, rough, bead-like in- 

 crustations upon the branches of the Sickle Coralline. 



Lepralia hyalina — A polyzoon which forms a thin calcareous crust, 

 or network, upon rocks, seaweeds, corallines, shells, &c, and com- 

 mon on all parts of the coast, is, I believe, the species incrusting the 

 egg of a small Dogfish, to which are also attached several young shells of 

 Anomia. 



Memlranipora pilosa. — This polyzoon forms a very beautiful in- 

 crusting network of cells, and is said to be abundant on the Laminarian 

 and other weeds, and to be not uncommon on old shells. In the pre- 

 sent instance it was found covering the fronds of Fucus serratus. 



Flustra foliacea, Broad-leaved Horn wrack, or Seamat A well- 

 known polyzoon, common everywhere on the coast, and particularly so at 

 this locality. 



Alcyonium digitatum, Dead Men's Toes or Hands. — The spongi- 

 form masses, orpolypidom, of this the most common of marine animals, 

 were found to be very abundant. When fresh thrown upon the shore, and 



