MARINE ZOOLOGY 



10. Membrartipora monostachys. Busk. 

 Colony incrusting, branching and reticu- 

 lated. Zooecia ovate, slightly narrowed be- 

 low ; aperture oval, occupying two-thirds of 

 the front ; margins thin, bearing a central 

 spine below, and sometimes a pair near the 

 top; or armed with numerous (i8) delicate 

 spines pointing inwards. Yarmouth, on mus- 

 sel shells, etc., abundant (Harmer). 



The variety fossaria, forming friable sponge- 

 like masses on the stems of plants, occurs near 

 Yarmouth in ditches of brackish water a mile 

 from the sea (Wigham). 



11. Membrartipora pi/osa (Linn.). 



Colonies in large flat incrusting sheets on 

 Fucus and other weeds, between tide-marks. 

 Aperture oval, surrounded by numerous mar- 

 ginal spines (4-12), which bend inwards; a 

 long horny spine usually present behind the 

 area. Cromer (Harmer), Hasborough (P.), 

 Yarmouth (Harmer). 



12. Cribrilina annulata (Fabr.). 



Colonies forming small circular reddish 

 crusts on Lamlnaria^ shells or stones. Zooecia 

 ovate, convex ; the sides wrinkled. About 

 6 pairs of perforated centripetal furrows. The 

 raised calcareous bars between the furrows 

 represent the marginal spines of Membranipora 

 fused into a roof over the membranous aper- 

 ture. Orifice suborbicular, with a thickened 

 rim and 3 (or 4) terminal spines. Inside a 

 mussel-shell off Yarmouth (P.). 



13. Schizoporella llnear'n (Hassall). 



Colony incrusting, rose-coloured. Zooecia 

 entirely calcareous, rhomboidal, in regular 

 rows, separated by raised lines ; orifice round, 

 with^a pointed notch below, and 2-4 spines 

 above. Avicularia minute, elevated, usually 

 one on each side behind the orifice. On 

 Sahellaria tubes, Yarmouth (Harmer). 



14. Mucronella peachii (Johnst.). 



Colonies incrusting, calcareous, large, flat, of 

 irregular outline ; on Laminaria, shells, stones, 

 etc. Zooecia ovate, globose, notched around 

 the margin (a relic of the gaps between ances- 

 tral roofing spines, cf. Cribrilina). Orifice 

 subquadrangular, mucronate, with 6 spines or 

 denticles. No avicularia. Off Cromer and 

 Hasborough (P.). 



15. Lepralia pertusa (Esper). 



Colonies calcareous, circular, incrusting, 

 orange-coloured, with a glistening lustre. 

 Zooecia large, ovate, tumid, closely punctured ; 

 orifice circular. Avicularia rare; small, oval, 

 placed on one side near the orifice. On shells, 

 stones, etc. Off Hasborough (P.). 



16. Cellepora costazii, Andouin. 



Colonies minute, calcareous, incrusting ; 

 on stems of sertularian hydroids and algae. 

 Zooecia crowded, ovato-cylindrical ; orifice 

 terminal, with a prominent knob on each side 

 bearing a minute avicularium. Off Has- 

 borough (P.). 



II. CTENOSTOMATA 



17. Alcyonidium gelatinosum, Linn. 

 Colonies erect, gelatinous, smooth, lobed 



and branched, yellowish in colour. Height 

 usually 3 to 1 8 inches. Off Yarmouth (P.). 



18. Alcyonidium mytili, Dalyell. 



Colonies incrusting, fleshy, dingy white, 

 the surface finely papillated and showing the 

 hexagonal boundaries of the zooecia. Com- 

 mon on shells, etc., Yarmouth (Harmer). 



19. Vesicularia spinosa (Linn.). 



Colonies arborescent, horny, very delicate ; 

 the main stems zigzagged, the branches dicho- 

 tomously branched, bearing oval transparent 

 zooecia at intervals. Height 4-12 inches. 

 On stones, oyster-shells, etc. Off Yarmouth, 

 common (Harmer). 



20. Amathia lendigera (Linn.). 



Colonies arborescent, in tangled masses on 

 fibrous algae and zoophytes. Zooecia cylin- 

 drical, disposed in small groups immediately 

 below the forks of the branches, each group 

 consisting of 4-8 pairs arranged in two con- 

 tiguous parallel rows. Tentacles 8. Yar- 

 mouth (Harmer). 



2 1 . Bowerbankia imbricata (Adams), var. densa. 

 Colonies (in the variety) consisting of large 



cylindrical transparent zooecia, disposed in 

 groups along a creeping stolon. Tentacles 

 10. On Flustra, Yarmouth (Harmer). 



22. Triticella flava, Dalyell. 



Zooecia laterally compressed, erect, ovate, 

 attached to a creeping stolon by short stalks, 

 on which they are movable. On backs of 

 crabs [Portunus holsatus), Yarmouth (Harmer). 



III. CYCLOSTOMATA 



23. Crisia aculeata, Hassall. 



Colonies in small white tufts, the branches 

 curling inwards. Zooecia tubular, calcareous, 

 in double series, many bearing a long spine 

 near the top ; the series are divided into seg- 

 ments by yellowish horny joints. Height 

 ^— I inch. Yarmouth, on Flustra, Fesicularia 

 and Hydroids (Harmer). 



24. Diastopora patina (Lamarck). 



Colonies small {\ inch diameter), white, 

 calcareous, discoid ; surrounded by a broad, 



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