TUNICATA. 



1243 



There have been certain organic remains* 

 figured and described as belonging to the 

 Tunicate family, but which (with the exception 

 of the obscure and indeterminate Ischadites 

 Kcenigii) have been found to belong to the 

 family of the Cystidea of Von Buch, closely 

 allied to the crinoidean family of the Radiata. 



At first sight there is considerable resem- 

 blance between many of these cystidean forms 

 and the ascidian genus Boltcnia, the body 

 being globose or subcylindrical and pedun- 

 culated. In the Cyttidea there are two more 

 or less terminal orifices, and a third lateral 

 aperture. The whole animal is coated with hex- 

 agonal plates variously ornamented ; the stem, 

 perforated throughout and giving evidence 

 of quinary arrangement. "The mouth," says 

 Von Buch, " is planted in the central part of 

 the upper surface, generally in a moveable 

 proboscis, covered with minute plates ; the 

 anal orifice is small, close to the mouth, per- 

 forating a plate, not surrounded by separate 

 valvules ; and the third aperture, probably 

 the ovarial orifice of the animal, is placed 

 further towards the middle, but almost inva- 

 riably on the upper half of the body on which 

 the mouth is placed. It is round or oval in 

 form, not connected with the mouth, and often 

 covered by a five or six-sided pyramid, which 

 seems to be composed of as many little valves." 



We have introduced this description that 

 we may here point out the general similarity 

 of the external form of these obsolete radiate 

 animals to some of the ascidian group, and 

 that we may in particular point out the very 

 similar armature of ornamented hexagonal 

 plates present in Che/yosoma, with its valve- 

 surrounded orifices. With regard to the ad- 

 ditional orifices, we have but to lengthen out 

 the oviduct or efferent vessel of the Atctdia, 

 and continue it to the surface, as in the mal- 

 formation noticed and drawn by John Hunter, 

 and a very similar arrangement of parts will 

 apparently exist. 



There are several points of analogy between 

 some forms of Ascuiue and of Zoophyta asci- 

 doida (Bowerbankia, &c.) and the Radiata: 

 into this subject we must not now enter ; we 

 can only allude to the observations of Messrs. 

 Forbes and Goodsir on the Pelonaia (see 

 p. 1239.), and leave the subject open to further 

 investigation. 



BIBLIOGRAPHY. Besides the works, connected 

 with the subject, that are referred to in the text, 

 the following are some of the most important : 

 Peron, Memoire sur le Noveau Genre Pyrosoma. 

 Annales du Museum d' Histoire Naturelle, t. iv. 1804. 

 Lesueur, Memoire sur 1'Organisation des Pyrosomes, 

 et sur la Place qu'ils doivent occuper dans une 

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 Physique, Juin, 1815, t. Ixxx. Desmarest et 

 Lesueur, Memoire sur le Botrylle etoile (Botryllus 

 xtellatus). Lu a la Socie'te Philomatique de Paris, 

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 t. Ixxx. Desmarest et Lesueur, Extraits de deux 

 Memoires lus a la Societe Philomatique de Paris, 

 en Mars et Avril, 1815, sur 1' Organization de deux 



* Leucophthalmus, Kcenig (Sphceronites), Sa- 

 conites, Rafinesque, &c. 



Animaux Marins places jusqu'ici dans la Classe des 

 Radiaires, et qui doivent etre rapportes a celles des 

 Mollusques, &c. Bulletin de la Societe Philoma- 

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 Memoire sur les Thalides ( Thalia, Brown), et 

 sur les Biphores (Salpa, Forskaohl). Annales du 

 Museum d'Histoire Naturelle, t. iv. 1804. Cuvier, 

 Memoire sur les Ascidies et sur leur Anatomic. 

 Memoires du Museum d'Histoire Naturelle, t. ii. 

 1815. Chiaje, S. delle, Memoria sulla Storia e 

 Notomia degli Animali senza Vertebre del Regno 

 di Napoli, 4 vols. 4to. Napoli, 18231829. Ibid. 

 Figure, 4to. 18221828. Savigny, J. (7., Me'- 

 moires sur les Animaux sans Vertebres, pt. i. and 

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 MOLLUSCS. Quoy et Gaimard, Voyage de 1'Astro- 

 labe, Zoologie, t. iii. Quoy et Gaimard, Voyage 

 de 1'Oranie, t. ii Blainville, Dictionnaire des Sciences 

 Naturelles, art. Mollusques. Cluimisio, Dissertatio 

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 na^ana. Fasc. 1. De Salpa. Berolini, 1819, 4to. 

 MacLeay, Anatomical Observations on the Natural 

 Group of Tunicata, with the Description of three 

 Species collected in Fox Channel during the late 

 Northern Expedition. Read June 15. 1824. Trans. 

 Linn. Soc. vol. xiv. 1825. Meyen, BeitrSge zur 

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 Erste Abtheilung, iiber die Salpen. Nova Acta 

 Acad. Caes. Leop. Car. Natur. Curios, t. xvi. pars 

 prior, 1832. Eschricht, Anatomisk-physiologiske 

 Undersogelser over Salperne. Royal Danish Trans- 

 actions, vol. viii. 1841. Eschricht, Anatomisk 

 Beskrivelse af Chelyosoma Mac-Leayanum. Royal 

 Danish Transactions, vol. ix. 1842. Sars, Beskri- 

 velser og lagttagelser oder Nogle Maerkelige eller 

 nye i habet bed den Bergenske Kyst lebende dyr 

 af Polypernes, Acalephernes, Radiathernes, An- 

 nelidernes og Molluskernes Classer, 4to. Bergen, 

 1835. Sars, Fauna littoralis Norwegian, 1st part 

 ( Salpee). JDalzell, A singular Mode of Propagation 

 among the lower Animals (Ascidia and Aplidium). 

 Edinb. New Philos. Journ. vol. xxvi. 1839; and 

 Isis, viii. 1839. Dalzell, On some of the rarer 

 Animals on the Coast of Scotland, &c. Home ( Sir 

 E.}, Lectures on Comparative Anatomy, vol. ii. 

 (Salpa). 4to. London, 1814. Cams, Beitrage zur 

 Kenntniss des inneren Baues und der Entwicke- 

 lungs Geschichte der Ascidien. Nov. Act. Nat. 

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 Physiologic der Seescheiden. Meckel's Archiv. f. 

 Physiol. B. ii. H. iv. Cams, Anatomic Compar. vol. 

 ii. Eysenhardt, Ueber einige merkwurdige Lebens- 

 erscheinungen an Ascidien. Nov. Act. Nat. Cur. 

 t. xi. Lister, Phil. Trans. 1834, part ii. Milne Ed- 

 wards, Observations sur les Ascidies Composees, qui 

 se trouvent aux Cotes de la Manche. Mem. Acad. des 

 Sciences, t. xviii. Milne Edwards, Sur la Circula- 

 tion du Sang chez les Pyrosomes. Comptes Rendus 

 de 1'Acad. des Sciences, t. x. 1840, p. 284 ; Sur la 

 Circulation et sur 1'Existence d'un Systemes Ner 

 veux chez les Salpes. Ibid. p. 408. Annales 

 des Sc. Nat. 2de series, t. xiii. Milne Edwards, 

 Recherches Zoolog. faites pendant un Voyage en 

 Sicile. Comptes Rendus, 1844, t. xix. p. 1137. Milne 

 Edwards et Audouin, Resume des Recherches 

 faites aux lies Chaussey. Ann. Sc. Nat. t. xv. 

 Gervais, Suppl. Diet. Sc. Nat. Ime vol. art. ASCI- 

 DIES. Costs, Recherches sur PAppareil respira- 

 toire des Ascidiens. Comptes Rendus, 1842, t. xiv. 

 Broderip and Sowerby, Observations on New Mol- 

 lusca, &c. (Chelyosoma) Zoolog. Journal, vol. v. 

 Johnson, Mag. Nat. Hist. 1834 (Aplidium). Penny 

 Cyclopaedia, articles SALPACEA and TUNICATA. Van 

 Beneden, Recherches sur 1' Embryogenie, 1'Ana- 

 tomie, et la Physiologic des Ascidies Simples. 

 Memoires de 1'Academie Royal de Belgique, t. xx. 

 1847. Forbes (E ), Forbes and Hanley's History of 

 British Mollusca, 8vo. London, parts i. and ii. 1848. 

 (T. Rupert Jones) 



