06 HISTORY. 



of his CristatcUa miralilis. He has observed the eplstome, aud accurately describes the 

 statoblasts, which he has seen to open for the escape of the young. 



In 1834, M. De Blainville published the first edition of his ' Manual of Actinology.'* 

 In this he constitutes a distinct sub-class of his Polypiaires, under the name of PoJjjpiaria 

 duhia for such as have the tentacula borne upon two diverging arms, in the form of a horse- 

 shoe. It includes the fresh-water genera then known, namely, CristafeUa, FlmnateUa, and 

 Alcyonella, together with the Dijflugia of Leclerc — an animal in no way related to them — and 

 the marine genus DedaJaa, established by Qnoy and Gaimardf for a very singular animal dis- 

 covered by these naturalists in the seas of the Mauritius, and with which we are but very 

 imperfectly acquainted. De Blainville's location of the Dedalcea in his Polj/piaria duhia is 

 founded on the examination of a specimen brought home by Quoy and Gaimard, and preserved 

 in spirits, and the genus is certainly incorrectly associated with the fresh-water forms. In 

 subsequent editions of his 'Manual,' M. De Blainville alludes to the locomotive embryos 

 described by Meyen, but cannot bring himself to admit the correctness of this observation. 



In 1835, M. Dumortier published, in the ' Bulletin de I'Academie de Bruxelles,' a 

 memoir on the " Polype a Panache " of Trembley.J This Polyzoon, which had been pre. 

 viously confounded with Alcyonella and Plinnatella, was believed by Dumortier to be 

 sufficiently distinct to render it the type of a new genus, which he accordingly constituted, 

 under the name of Lophopus. In consequence of using lenses of.too low a power, Dumortier 

 persuaded himself of the absence of cilia on the tentacula, and made this supposed fact the 

 principal character in his new genus. Notwithstanding, however, the erroneous observation 

 on which Dumortier thus relied, the separation of the " Polype a Panache " from the other 

 fresh-water Polyzoa was an important step, and is fully borne out by its general structure. 



The memoir of Dumortier is chiefly valuable as giving us the most complete account 

 of the anatomy of the Polyzoa which had up to his time been published. To him is 

 due the honour of having been the first to demonstrate a distinct nervous system in these 

 animals; and he describes the cutaneous, circulatory, respiratory, manducatory, digestive, 

 muscular, and reproductive systems, with much detail, and with a correctness which makes us 

 the more surprised that he should have committed so grave an error respecting the tentacular 

 cilia. 



In the ' Bulletin Zoologique ' of the same year, M. Gervais gives an analysis of the 

 memoir of M. Dumortier, and contends against the right of the "Polype a Panache" to 

 assume the position of a distinct genus, insisting on its being nothing more than a Pliimatella. 



In the year 1837, M. Turpin read before the Royal Academy of Sciences at Paris a 

 memoir on Cristatella.^ He had received, a short time previously, from M. Gervais, 

 certain minute seed-like organic bodies, which this naturalist had discovered in the Canal 

 d'Ourque, in the city of Paris. M. Turpin, suspecting them to be the ova of some aquatic 



* De Blainville, 'Manuel d'Actinologie et de Zoophytologie.' Paris, 1834. 



f Quoy et Gaimard, ' Zoologie du Voj-age de 1' Astrolabe.' Paris, 1830-33. 



+ DuMOKTiER, Keclierclies sur rAnatomie et la Physiologie des Polypiers composes d'eau douce. 

 ' Bull. Acad. Brux.,' ii, p. 422. 



§ Turpin, Etude microscopique de la Cristatella mucedo. ' Comptes rend, de TAcad. Sci. Paris,' 

 Jan., 1837 ; and 'Ann. Sci. Nat.,' 2° ser., vii, p. 65. 



