MARINE ZOOLOGY temperature, together with a considerable number of periodic migrants, which are attracted from the south in early summer, and probably from the north and east in autumn, owing to the peculiarities of temperature which characterize East Anglian waters in those seasons. Purely northern or purely southern types are exceptionally scarce in the resi- dent Norfolk fauna. Out of a total of thirty-one recorded hydroid zoophytes two only can be said to have a restricted distribution, viz. the southern Coryne vaginata and the northern Sertularia Jilicula. Out of twenty-six recorded Polyzoa two only are northern types, viz. Menipea ternata and Cribrilina annulata, and five are more or less southern types, viz. Scrupocellaria scrupea, Bugula plumosa, Membranipora lacroixit and monostachys, and Amathia lendigera. It appears to be particu- larly significant that Bugula purpurotincta, a close relative of B. plumosa, but a purely northern type, has not been obtained south of Flamborough Head, though abundant along the coast from Scarborough to Wick. The creeks and waters of East Anglia appear to be the headquarters of Membranipora monostachys, which nowhere attains such luxuriance of growth and numbers as here. Out of twenty recorded chstopod worms all are common wiae- ranging forms, except Eulalia sanguinea and possibly Sabellaria spinulosa, which are distributed principally to the northward. In the following records I have relied principally upon the reports' of the surveying cruise of the German ship Pommerania in the summer of 1872 i^ahresbericht d. Commission z. wiss. Untersuchung d. deutschen Meere in Kiel, ii. and iii. 1875). The valuable information in these reports has been supplemented from notes or specimens communicated to me by various Norfolk naturalists, among whom I desire to thank especially Dr. S. F. Harmer of Cambridge ; Mr. H. D. Geldart, Mr. Thomas Southwell, and Mr. R. A. Todd of Norwich ; and Mr. A. Patterson of Yarmouth, for their kind and willing assistance. CCELENTERATA {Jellyfish, Sea Anemones, etc.) Stinging animals, of circular outline, having all their organs radially arranged round a central mouth ; free-swimming [e.g. meduss) or sedentary [e.g. hydroid zoophytes, sea anemones) ; solitary {e.g. medusae and anemones) or subdivided into ' colonies ' by budding {e.g. hydroid zoophytes). The units in the colonies are known as polyps. I. HYDROZOA 2. Hydractinia echinaia (Fleming). I. Hydroid Zoophytes Incrusting the shells of univalves (esp. Colonial, forming arborescent or encrusting ^™'" ^"^ Natka) ttnzntcA by hermit stocks, attached to stones, shells, worm-tubes "^- ^^ Yarmouth (P.). and seaweeds. 3. Coryne vaginata, Hincks. Nomenclature : Hincks, British Hydroid Zoo- Cromer (H. D. Geldart) ; Hasborough (R. phytes, 1868 (= H). A. Todd). I. Cordylophora lacustris, Allman. 4. Hydranthea margarica, Hincks. In brackish or fresh waters. Near Kings Off Yarmouth, growing on Flmtra foUacea Lynn (Dr. Low). (Dr. S. F. Harmer, 1899). ' For the sake of brevity the Pommerania records are indicated in the sequel by the letter P. 79
