33 



Animals enter the bladder by bending inwards the posterior free 

 edge of the valvo, -which from being- highly elastic shuts again 

 instantly. As the edge is extremely thin, and fits closely against 

 the edge of the collar, both projecting into the bladder, it would 

 evidently bo very difficult for any animal to get out when once 

 imprisoned, and, apparently, they never do escape. Darwin re- 

 marks, " To show how closely the edge fits, 1 may mention that 

 my son found a Daphnia, which had inserted one of its antcnnte 

 into tlie slit, and it was thus held fast during a whole day." For 

 further information concerning this interesting plant 1 beg to refer 

 the member's to Darwin's work, which is in the .Society's library. 



In one of the bladders of the specimen before the meeting there 

 are no less than six animals of the genus cypris, having a body 

 enclosed entirely in a covering of two valves, resembling a bivalve 

 shell, belonging to the order " Ostra-coda," from the Greek word 

 signifying a shell. The same bladder also contains a globule of 

 air. The measurements of the bladder are as follows: — Long 

 diameter, 2-2.3 inch; short diameter, 2-30 inch. The measure- 

 ments of each separate animal contained therein are: — Long 

 diameter, 1-50 inch; short diameter, 1-75 inch. 



Captain ilcDakiu, in communicating some of his experiments on 

 the absorbing power of chalk, dwelt on our present knowledge of 

 its origin and properties, commencing with its position as the con- 

 cluding formation of the great secondary division when the saurian 

 type of creation gave place, in the next great division, the tertiary, 

 to the more perfectly tleveloped mammal. 1'Jie chalk being a marine 

 foiTOationthe fossils are almost exclusivtdy of that nature, with thefcw 

 exceptions of drift wood and bones of the gigantic lizards of the land, 

 and not only this, but the whole mass consists of the remains of 

 Foraminiferac, minute creatures, whose calcareous shells, too small 

 to be easily discerned by the unaided eye, contribute in some instances 

 ninety-eight per cent, of the whole, and in the underlying green- 

 sand internal casts in silica of these creatures occur. This is very 

 remarkable, as pointed out by Dr. Carpenter, who has shown that 

 the same process of nature is now going on, forming a white mud 

 at the bottom of the Atlantic, so familiar to readers of his works, 

 as the Globigeriua ooze. Below the depth of twelve thousand feet 

 the calcarious particles are re-dissolved and the silicious casts of 

 their interiors take their i)laco, constitutinga similar formation in this 

 respect to the green sand of the cretacious period. The importance 

 of these creatures in the eartli's economy may be concluded from 

 the estimation that has been made, that all the animal and vege- 

 table life besides is small compared to the immense quantity of life 

 represented by the Forarainiferse. It furnishes one of those curious 

 analogies that exist in nature, in its similarity to electricity of 

 quantity and intensity ; life in these creatures representing quantity, 

 while in the higher animals it may take the form of intensity. Nor 



