Genus Bollenta, Savigny ; synonym, Ascidia, Auct.— Body more or less globular, fixed, pe dunculated, attached sometimes to the stem of another individual ; test coriaceous; ori fices lateral, and- each cleft into four rays ; branchial sac longitudinally plicated ; sur mounted by a circle of compound tentacula.
Genus Cystingia, MacLeay. — Body glo bular, fixed, pedunculated ; test subcoriaceous ; branchial orifice quadrifid, lateral ; anal irre gular, terminal ; branchial sac plicated; tenta cula compound.
Genus Bipapillaria, Lamarck. —Body more or less globular, free, pedunculated ; test mem branous ; the extremity of the body opposite to the attachment of the peduncle bearing two equal, conical papillm, having their apices per forate ; each orifice furnished with three very short, stiff, setaceous, retractile tentacles.• Genus Perophora, Wiegmann.*—Individuals pedunculated, suborbicular, compressed ; tho rax not lineated by granular bands.
Family BOTRYLLID)E, MacLeay. Syno nyms : Aleyonia, Auct. prior. ; Telhyes corn posees, Savigny ; les Reunis ou Botryllaires, Lamarck ; les Agreges, Cuvier ; Ascidiacea, pars, Blainville; Ascidies composees, Milne Edwards ; Polyascidiens, Van Beneden.
Body compound, fixed ; animals associated; the tests fused together, forming'a common mass in which the animals are imbedded in one or more groups or "systems ;" the indi viduals not connected by any internal union ; oviparous and gemmiparous.
" If, when walking on the sea-shore, about low-water mark," says the distinguished na turalist previously quoted, " we turn over large stones, or look under projecting eaves of rock, we are almost sure to see translucent jelly-like masses of various hues of orange, purple, yellow, blue, grey, and green, some times nearly uniform in tint, sometimes beau tifully variegated, and very frequently pen cilled as if with stars of gorgeous device ; now encrusting the surface of the rock, now descending from it in icicle-like projections. These are compound Ascidians. A tangle or broad-leaved focus, torn from its rocky bed, or gathered on the sand, where the waves have cast it after storms, will show us similar bodies, mostly those star-figured, investing its stalks, winding among the intricacies of its roots, or clothing with a glairy coat the ex panse of its foliated extremities. . . . In
examining these bodies, we find that it is not a single animal which lies before us, but a commonwealth of beings, bound together by common and vital ties. Each star is a family, each group of stars a community. Individuals are linked together in systems, systems com bined into masses. . . . Indeed, few bo dies among the forms of animal life exhibit such exquisite and kaleidoscopic figures as those which we see displayed in the combina tions of the compound Ascidians." Previous to the researches of Savigny, the Botryllid.T were regarded as Alryouia ; Gaert ner (1774) and Renieri (1793) being the only naturalists who had suspected their compound nature and true affinities.* " The Memoir of Savigny, published in 1816, however, threw entirely new and unanticipated light on their nature. He showed that they were essentially Ascidians, differing from the simple forms only in being united into more or less complicated systems." t In the arrangement of Professor Milne Edwards the family is subdivided as follows : The tribe Polyclinina (les Polycliniens, Milne-Edwards) is characterised principally by the division of the body into three distinct portions, viz. a thorax, a superior abdomen, and a post-abdomen. It has, however, other anatomical peculiarities, such as the great de velopment of the organs of generation, and the position of the heart at the inferior extremity of the body. This group comprehends nu merous species, and is divisible into two natural sections, recognised by the external conformation of the anal orifice. In one di vision (P. bistellata) this orifice is surrounded with a regular circlet of rays or marginal lobules, and is exactly similar to the branchial orifice. In the other division (P. unislellata) the anal differs from the branchial orifice in not being rayed, or at least in having merely irregular marginal lobules.
Genus Sigillina, Savigny. — Common body a solid, elongated, erect cone ; gelatinous, pedunculated, isolated or attached to similar cones, consisting of a single system of many individuals disposed one above another in irregular circles ; branchial and anal orifices each with six rays ; abdomen larger than thorax ; post-abdomen long and slender (fig. 769.).