Bibliographical Notices. 311 



perhaps from the commencement and its full development thereby 

 having been unimpeded, and states that the Proteus feeds upon 

 its like as well as upon other matter, inclosing its food within its 

 own substance after the manner of the Hydra. 



"While examining the transparent border of a portion of sponge 

 growing from the seed-like bodies, he has observed the contract- 

 ing vesicles distinctly, and a little within this, the animals them- 

 selves distinguishable, though amassed together and ever chan- 

 ging their form ; but he does not appear to have ever seen them 

 inclose an object within their substance after the manner of the 

 Proteus. 



In the development of the contents of the sporangia or seed- 

 like bodies, he observes, that when the latter are opened under 

 water in a watch-glass, the transparent cells within them, having 

 been eliminated, swell and are bursted by the imbibition (endos- 

 mose) of that fluid ; and that then the true ova of the Sponge with 

 which they are filled, spread themselves over the surface of the 

 vessel. Each ovum appears, not to be globular or ovoid as he 

 formerly supposed, but discoidal, very much resembling in size 

 and appearance the globules of the blood, it being only when 

 they are turned on their edges that they appear ovoid. The red 

 spot in their centre he also now thinks to be an optical illusion, 

 while he has every reason to believe that the ovum retains its 

 planiform state until its transparent vesicles and granules have 

 become developed and the power of locomotion in it fully esta- 

 blished. — Ed. 



BIBLIOGRAPHICAL NOTICES. 



Rare and Remarkable Animals of Scotland, represented from living 

 Subjects ; with practical Observations on their Nature. By Sir 

 John Graham Dalyell, Bart. Volume first, containing fifty- 

 three coloured Plates. London : John Van Voorst, Paternoster 

 Row, 1847. 4to. Pp. 270. 



[Continued from p. 139.] 



The most interesting chapter in this interesting volume is that 

 which narrates the history of the Hydra tuba. This marine animal 

 is called a Hydra by our author because it has the form and the cha- 

 racters of the freshwater polypes, and possesses also their qualities — 

 their greed of living prey (p. 87), their proliferous evolution of 

 young, their endurance of privations, their power to recover from 

 apparently immedicable wounds, and their strange germinations and 

 monstrosities under the influence and direction of the experimen- 

 talist (p. 93). This hydra is found attached to submarine bodies ; 

 the body is fleshy, inversely conical, encircled on the oral disc with 



