348 Bibliographical Notices. 



cell may be considered as the analogue of the yolk or rather of the ve- 

 sicle of Purkinje or of Wagner. It enlarges rapidly ; and soon there 

 is distinguishable underneath it a membrane which has its inferior 

 surface in contact with the circulating fluid. This membrane is the 

 source of the new polyp, the progress of which onwards from a little 

 cone to the time when it has assumed the form of a Bero'e, and is 

 detached from its matrix and floats at freedom in the sea, is most in- 

 terestingly told. Van Beneden has not seen this nomade Bero'e refix 

 itself, but he has seen it very soon afterwards ; and its transition from 

 the condition and shape of a medusa to that of its parent polyp ap- 

 pears as an uninterrupted sequence of development. He has never 

 discovered cilia on the young embryo, nor any organs of sense. 



3. The development from a simple eg^ is the most regular, and the 

 process which approaches nearest to that of the superior animals. 



4. The development from a compound or divided yolk is the most 

 remarkable ; but when it is remembered that, in these polyps, every 

 portion of the body can give origin to a new individual, we need be 

 the less surprised to find that the vitellus should have the same qua- 

 lity. At first the process in the primary cell agrees with the other 

 developments, but a time comes when the surface of the vitelline 

 mass assumes an embossed or granular appearance, and instead of a 

 single vitellus there are as many as there are granules. In each of 

 these there is the vesicle of Purkinje, or at least a transparent central 

 vesicle. It seems that the embryos thus formed diflfer from the 

 others not only in bulk but also in shape, for in Campanularia M. 

 Loven has seen them, covered with cilia, leave their cell, and move 

 about like infusorial animalcules. 



5. This is the union of two of the preceding modes ; the forma- 

 tion at one and the same time of a free bud and of a compound vi- 

 tellus organizing itself in the interior of this bud. It is the fact of 

 these buds containing these vitelli that has made them be taken for 

 pregnant females. The eggs here, according to Loven, are covered 

 with cilia ; and when the embryo is bom (for we should remember 

 that the polyps are viviparous) it has the aspect of a Planaria, — the 

 planule of Sir J. G. Dalzell. 



Van Beneden next proceeds to prove, by a comparison of their 

 common resemblances, that the Campanularia and TuhularicB are so 

 nearly related that they may almost be considered as members of the 

 same family. 



Lastly, he reviews the family zoologically, giving its character in 

 detail, and the characters of the genera and species which he has ob- 

 served. This view has been already given in the ' Annals.' We 

 need only remark that his Tuhularia calamaris is really not the T. ca- 

 lamaris of Pallas or T. indivisa of Linnaeus ; and his T. Dumortierii 

 is a common British species. M. de Blainville is not the first of 

 modern authors who recognised that the Syncoryne ought to be placed 

 near the Tuhularice (p. 51), as any one may see by referring to Lou- 

 don's ' Magazine of Nat. History,' vol. v. p. 632. We question the 

 validity of the distinction between Syncoryne pusilla and Listerii ; 

 they are both British species, but the latter is the commonest. Van 



