. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. TUNICATA. 1203 action of the cilia the currents arc sent in the direction of the oesophageal aperture. In Ascidia papillosa and Cynthia microcosm us, a little soft tubercle is situated on the interior of the branchial sac, not far from the orifice, between the two branchial veins, not observed in other Ascidians, but seen in all the Botryl- lians. On the internal surface of the sac are also seen several prominent lines, 12-15 in A. mammillaris and A. papillaris, 5-6 in C. am- pulla, more or less distant from one another
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. TUNICATA. 1203 action of the cilia the currents arc sent in the direction of the oesophageal aperture. In Ascidia papillosa and Cynthia microcosm us, a little soft tubercle is situated on the interior of the branchial sac, not far from the orifice, between the two branchial veins, not observed in other Ascidians, but seen in all the Botryl- lians. On the internal surface of the sac are also seen several prominent lines, 12-15 in A. mammillaris and A. papillaris, 5-6 in C. am- pulla, more or less distant from one another according to their length. These are folds forming gutters converging towards the mouth, and having also transverse channels leading from one to another. Above they appear to terminate in culs-de-sac. The vibratile cilia covering them are very long and numerous. Van Beneden found that, on placing for a short time a living Ascidian in water coloured with carmine, the particles of the colouring matter quickly filled these little ducts, making them appear like injected vessels. This dis- tinguished naturalist considered them to be somehow connected with the digestive appa- ratus, moulding, perhaps, the particles of food into cord-like masses before entering the stomach. In Chclyosoma (jig. 777. z) there is a remark- Fig. ,my of Clielyosoma Macleayanum. (After Eschrieht.) The inner or under side of the superior plated surface of the animal is shown, the branchial cavity being split open, and the abdominal viscera re- moved, a, branchial orifice, partly closed by a membrane, and surrounded by its hexagonal sphincter muscle and the accompanying six fan- shaped muscles; b, anal orifice, similarly provided with muscles; e, f, muscles bordering the carapace- plates ; el, the central hexagonal plate; e, e, e, e, the surrounding plates; f, the nerve-ganglion and nerve-fibres; </, h, the auditory apparatus ( ?) : i, the row of tentacles anterior to the oesophagus; j, stem a
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