COMPENDIUM OF GENERIC DISTINCTIONS. 



625 



Family. ASCIDIADiE. — Animal solitary or gregarious, simple 

 and fixed. ( (viperous. 



Genu*. Ascimi'M. — Body sessile; tests leathery or gelatinous; 

 branchial orifice with eight lobes, a circle of filaments within; 

 branchial sac simple. Northern Hemisphere. 



Genus. Cynthia. — Test leathery, sessile; orifices with four 

 lobes ; branchial sac plaited, tipped with filaments. Northern 

 Hemisphere. 



Genus. Pelos.ua. — Body long, cylindrical; orifices four- 

 cleft; mantle adhering to test. Northern Hemisphere. 



Genus. Boltema. — Test leathery, globular, on footstalk; 

 orifices at sides four-cleft ; branchial sac plaited. Many seas. 



Family. CLAVELLINiE. — Animals compound and fixed, con- 

 nected by tunic or gelatinous base. 



Genus. Clavellixa. — Body long, erect, on footstalk; test 

 transparent and smooth; orifices simple. Many seas. 



Genus. Syntethys. — Animals gelatinous, sessile; orifices 

 simple. Northern seas. 



Family. BOTRYLLIADiE.— Animals compound ; tests fused 

 together. Oviparous and gemmiferous. 



Sub-family. Botryllina. — Animals united in systems round a 

 common cavity. Thorax and abdomen not distinct. 



Genus. Botryllus. — Test gelatinous or gristly; systems 

 round or star-shaped, individuals lying horizontally. Northern 

 seas. 



Family. PYROSOMIDJE.— Animal compound, free. 



Genus. Pyrosoma. — Body not contractile, cylindrical, hollow, 

 open at one end ; animals grouped in whorls on exterior. Warm 

 seas. 



Family. SALPIDJE. — Animals free, alternately solitary and 

 aggregated. 



Genus. Salpa. — Animal oblong, nearly cylindrical. Test 

 thin, transparent ; gill rudimentary. Alternate generations un- 

 like each other. Northern Hemisphere. 



Sub-class. POLYZOA- — Animals compound; digestive canal 

 with two apertures, replicate, the posterior ascending by side of 

 front portion. Mouth surrounded with tentacles. Front portion 

 retractile by inversion. 



Order. I N FU N Dl BU LATA. 



Sub-order. CHEILOSTOMATA— Aperture of cell filled 

 with thin membranous or chalky veil ; mouth crescent-shaped ; 

 lip moveable. 



Family. CATENICELLIDJE. — Cells connected by flexible 

 joints. 



Genus. Catexicella. — Cells facing same way; branches 

 dichotomous ; polyzoarv erect ; ovicells below opening of cell in 

 front. Bass's .Straits. Xew Zealand. 



Genus. Calpidium. — Avicularium on each side of cells; two 

 or more apertures all facing same way; cells single at dichoto- 

 mous fork. Bass's Straits. 



Family. SALICORNARIADiE.— Cells round imaginary axis; 

 branches cylindrical; polyzoarv dichotomous, erect. 



Genus. Salicokn aria. — Front of cell depressed, surrounded 

 by ridge, forming surface of polyzoary into hexagons or rhom- 

 boids. No apertures. Avieularia irregular. European and 

 other seas. 



Family. CELLUXARIDJE.— Cells in same plane; branches 

 linear, dichotomous, erect. 



Genus. Cellularia. — Cells bi-triserial, oblong or rhomboidal, 

 contiguous, perforated behind; no avicularium, seldom vibrac- 

 ulum. Britain, Ac. 



Genus. Mentpea.— Sessile avieularia on front of cell below 

 aperture. Britain, Ac 

 Voi.. ITT ?:» 



Genus. Scrupocellaria. — Cells rhomboidal. Sessile avicu- 

 larium on each cell. Aperture oval. Britain, &c. 



Genus. Casda. — No sessile avicularium; rest like Scrupo- 

 cellaria. Britain, Ac. 



Section. Polyzoary continuous. 



Family. SCRTJPARIAD5:.— Cells in single series. Joints not 

 flexible. 



Genus. ScrupaRia. — Cells decumbent; aperture oblique near 

 end. Branches from front of cell below aperture. Britain, &c. 



Genus. jEtea. — Cells tubular, erect, from creeping fibre. 

 Britain, &c. 



Genus. Beanta. — Polyzoary horny or chalky. Cells rising 

 from slender tube and open in front; edges with hollow spines. 

 Britain, Ac. 



Family. FARCIMINARIADJE.— Cells round imaginary axis, 

 alternate; polyzoary erect, dichotomous. 



Genus. Farciminaria . — Cells horny, flexible; edge raised; 

 apertures large. Tasmania. 



Family. GEMELLARIAD^;.— Cells opposite, in pairs. 



Genus. Gemellaria. — Cells back to back, pairs facing same 

 way; aperture oval, oblique. Britain, &c. 



Genus. Dimjstopia. — Cells back to back; pairs at right 

 angles. Bass's Straits. 



Genus. Notamia. — Avieularia tobacco-pipe-shaped above 

 each pair of cells. Britain. 



Family. CABEREADiE. — Polyzoary dichotomous; vibraeula 

 or sessile avieularia one to several cells. 



Genus. Caberea. — Vibraeula large, on back of branches. 

 Algoa Bay, &c. 



Family. BICELLARIADJE. — Vibraeula none. Polyzoary 

 dichotomous. 



Genus. Bicellaria. — Cells distinct; aperture upwards; 

 several spines. Britain, &c. 



Genus. Bcgcla. — Cells elliptical, contiguous; aperture 

 large. Britain, &c. 



Family. FLUSTRADJE — Polyzoary flat, flexible, leafy, erect. 

 Cells many. 



Genus. Flustra. — Cells contiguous, both sides of frond. 

 Britain, &e. 



Genus. Carbasea. — Cells contiguous, one side of frond. 

 Britain, ic. 



Genus. Diachoris. — Cells separate, each connected with six 

 others by tubular processes. Bass's Straits. 



Family. MEMBRAMPORIDJE. — Polyzoary flat, chalky, 

 mostly encrusting. Cells horizontal. 



Genus. Memrrampora. — Cells irregular or quincuncial, with 

 raised margins; part of front membranous and flexible. Brit- 

 ain, &c. 



Genus. Lepralia. — Polyxoary encrusting, spreading from 

 centre. Britain, Ac. 



Family. CELLEPORIDJE.— Cells vertical to axis or plane, 

 heaped or irregular. 



Genus. Celi.epora. — Polyzoary chalky, rigid, heaped or 

 quincuncial. Ascending beak or mouth, with avicularium. 



Family. ESCHARID.E.— Polyzoary erect; cells quincuncial 

 in same plane. 



Genus. Eschara. — Cells on both surfaces, back to back, 

 horizontal to plane of axis. Britain, &c. 



Genus. Retepora. -Polyzoary leafy, chalky, net-like. Cells 

 immersed, open on surface. 



