BOLTE'NIA, a subgenus of Ascidida', a family of the group Tuni rata, which, according to W. S. 3PLeny, are the animals that connect the Aerita, or lowest primary division of the animal kingdom, with the Mollusca, from which he observes they differ in the following points : first, in having an external covering consisting of an envelope distinctly organised and provided with two apertures, of which one is bmuchial, the other anal ; secondly, in their mantle forming an inter nal tunic) corremponding to the outer covering or teat, and provided like it with two openings ; and thirdly, in having branchim which occupy all or at least part of the membranous cavity formed by the internal sides of the mantle. From the A crita the Tunicata (or lietero branchiata, as De Blainville calls them) differ in having distinct nervous and generative systems, while their intestinal canal is pro vided with two openings, both internal. [Trzszcars.] The following is the generic character of lloltenia (Savigny) as reformed by M'Leay z—Botly with a coriaceous test, supported from the summit by a long pedicle, and having both orifices lateral and cleft into four rays. Bronchial pouch divided into longitudinal folds, surmounted by a circle of compound tentacula, and having the reti culation of its respiratory tissue simple ; abdomen lateral ; ovary multiple.
There are three species recorded, namely, B. orifera, B. lust fermis, And B. reniforniis.
The following is M'Lcay's character and deacrikztion of B. reni fermis (Asciclia globifera, Sabine, A. clarata, Fabricius) :—Obscure, roughish ; body sub-reniform, the orifices being somewhat prominent ; peduncle terminal ; envelope sub-pellucid, whitish ; mantle or tunic very thin, provided with transverse circular narrow muscles, which cut each other very obliquely ; tentacula about ten or twelve in number, very unequal, clavate, with the clava plumiform, or beau tifully divided into a number of regular lacinim ; branchial pouch marked with about fifteen or six teen large folds, and having the net-work simple and regular ; dorsal sulcus having the two lateral filaments winged and the intermediate simple ; cesophagus descending vertically to the lower end of the body, as suspended, and there meeting an ascending ovoidal stomach without any ap parent internal folioli; intestine with an oblong, longitudinal, open loop, which is prolonged to the pedicle ; rectum narrow, sub conical, and ascending nearly parallel to'the cesophagus, only higher ; anus having a scolloped margin; liver coating the stomach behind the right ovary, and run ning from the lower end of the body, as suspended, about half way up ; it is divided into several granulated globes, some of which are separated from the others, particularly towards the pharynx ; ovaries two, elongate, lobate, situ ated on each side of the body, and directed towards the anal orifice ; right ovary straight, claviform, lying close within the loop of the intestine ; left ovary larger and less lobate, but undulated and extending downwards behind the branchial vein.
M'Leay gives the northern seas of America as the locality of the animal. Captain J. C. Ross says that a single specimen was dredged up from a depth of seventy fathoms near Elizabeth Harbour. He observes that he can add nothing to DPLeay's admirable description except that the colour of the body is a very light brown ; that of the pedicle darker.
The sphere wherein this Ascidian moves must necessarily be very contracted. Anchored by its pedicle, the length of its moorings fixes the limit of its motions, which are most probably confined to the oscillations arising from the agitation of the waves. Both the body and pedicle, a9 M'Leay observes, are scabroee, or covered with a rough surface, which is formed by exceedingly short coarse hairs. The original colour he could not ascertain ; but in spirits it was cinereous, or dirty white, which, he adds, may possibly be the true colour of the animal, as it is not unfrequently that of the other Ascididm. M`Leay's specimen was brought home from Winter Island by W. N. Griffiths, Esq., while under the command of Captain (now Sir Edward) Parry. 2