A HISTORY OF NORFOLK 



V. GEPHYREA VI. CH.ETOGNATHA 



22. Phascolosoma vulgare (Blainville). 



Body cylindrical ; skin yellowish, smooth, 

 tough, shining. Proboscis about half the length 

 of the body, and invaginable into the latter ; 

 its anterior swollen part provided with a 

 diffuse band of small brown booklets, and 

 with 1 6 circumoral tentacles. Length 5-6 

 inches. Burrows in sand. 



23. Sagttta bipunctata, Quoy and Gaimard. 



Body cylindrical, elongated, transparent ; 

 provided with 2 pairs of lateral fins ; tail 

 fins small. Length | inch. Lives freely 

 floating in the sea. Mouth armed with lateral 

 hooks. 



VII. POLYZOA 



Animals of minute size, provided with a circlet of ciliated tentacles, and forming exten- 

 sive colonies, either reticulate, encrusting, or arborescent. The lower part of the body of 

 each individual (or zoouPj has usually a horny or calcareous skin, which forms a box or tube 

 (called the zocecium), into which the delicate upper portion can be quickly withdrawn for 

 purposes of protection. In the Cheilostomes the ' mouth ' of this box can be closed by a 

 movable lid (the operculum) which in certain modified zocecia of the colony is converted into 

 a snapping beak [avkularium) or a long slender spine {vihraculum) for cleansing the colony. 

 Nomenclature : Hincks, British Marine Polyzoa, 1880. 

 L CHEILOSTOMATA 



1. Eucratea chelata (Linn.). 

 Colony composed of a creeping base (usually 



lines of decumbent zocecia) and of delicate 

 branching shoots. Zocecia in single rows, 

 white, subcalcareous, expanding upwards ; 

 aperture oblique, margin unarmed ; often 

 bearing a short tubular appendage below the 

 aperture. Yarmouth, on Amathia and Veii- 

 cularia (Harmer). 



2. Menipea ternata (Ell. and Sol.). 

 Colony arborescent, forming delicate white 



tufts with curling branches on the larger 

 Hydroids {Hydrallmania, Sertularia, etc.) to 

 which it binds itself by numerous tendrils. 

 Zocecia tapering below, united in sets of three ; 

 ' aperture ' subterminal, oval, protected by an 

 overhanging fan-shaped spine, and 2 or 3 

 terminal spines. Large lateral avicularia. Off 

 Hasborough (P.). 



3. Scrupocellaria scruposa (Linn.). 

 Colony arborescent, forming stiff bushy 



tufts of a white colour. Zocecia in double 

 series. Aperture large, elliptical, with 2 

 slender spines only on each side above. 

 Under stones and on weeds, zoophytes, etc. 

 Off Hasborough (P.), Yarmouth (Harmer). 



4. Scrupocellaria icrupea^ Busk. 

 Like the preceding, but the aperture oval, 



and protected by an overhanging opercular 

 plate, as well as by 3 spines on the outer 

 margin above, and i, or occasionally 2, on 

 the inner. Off Hasborough (P.). 

 Scrupocellaria reptam (Linn.). 



5 



Colony forming stiff ragged sprays. Mar- 

 ginal spines as in S. scrupea, but the opercular 



84 



spine is branched and antler-like. Avicularia 

 and vibracula present in all three species. Not 

 yet recorded, but generally common between 

 tide-marks. 



6. Bicellaria ciliata (Linn.). 



Colonies pearly white, in delicate feathery 

 tufts. Zocecia biserial, alternate ; the ellipti- 

 cal aperture guarded by exceedingly long 

 marginal spines, viz. 4-7 above, i centrally 

 below, and i or 2 on the back. Yarmouth, 

 common (Harmer). 



7. Bugula plumosa (Pallas). 



Colony in tall feathery tufts, with fan-like 

 branches spirally arranged. Colour, when 

 alive, bright buff. Zooecia biserial. Aperture 

 large, with a single spine at the top. Avicu- 

 laria (' birds' heads ') very small. Recorded 

 off Hasborough and Lowestoft (P.), Yarmouth 

 (Harmer). 



8. Flustra foUacea (Linn.). 

 The ' sea-mat.' Colony erect, in large flat 



fronds of a brown colour, deeply divided. 

 Aperture with 2 marginal spines on each 

 side and often I at the top. Abundant off- 

 shore and thrown up in quantities on the 

 beaches (P.). 



9. Memhranipora lacroixii, Audouin. 

 Colony forming a thin gauze-like crust over 



shells and stones. Zocecia oval or elongated ; 

 aperture oval, occupying the whole of the 

 front ; margin thickened ; spines usually I 

 pair above, rarely numerous (11), and then 

 very delicate and pointing inwards. Abun- 

 dant on dead Mytilus shells and other objects, 

 Yarmouth (Harmer). 



