84 



Mr. Charlesworth then exhibited a series of specimens of the paper 

 nautilus, in several of which injuries to a very considerable extent 

 had been repaired with new substance agreeing in every respect 

 with the original shell ; affording the most decisive evidence that 

 the animal by which they were constructed possessed the same re- 

 parative powers as other testaceous molluscs. It would appear from 

 the observations of Captain Rang, who had recently repeated at 

 Algiers the experiments originally undertaken by Madame Jeanette 

 Power at Messina, that the Poulp does not fill up the breaches arti- 

 ficially produced in its habitation by a deposit of shelly matter, but 

 with a transparent diaphragm, which has neither the texture, white- 

 ness, or solidity of the original shell. This fact, in connection with 

 the specimens exhibited to the Meeting, appeared to Mr. Charles- 

 worth strongly to confirm the opinion entertained by Mr. Gray, De 

 Blainville, and others, of the parasitic character of the genus Ocythoe. 



Mr. Owen remarked, that he could not admit the validity of the 

 line of argument adopted by Mr. Charlesworth, because the dif- 

 ferences in the nature of the reproduced portions might depend 

 upon the particular part of the shell in which the perforation or 

 fracture had been effected, and a consequent difference in the repro- 

 ductive powers of the corresponding part of the mantle. 



not developed in the embryo, whose dissection is there figured, (PI. VII. 

 fig. 1.), yet the evidences of the ulterior development of an allantois in dif- 

 ferent marsupial genera, are described in the text, (p. 338, 342.) 1 therefore 

 took the opportunity of showing to Dr. Cosle during his visit to England the 

 foetal Kangaroo with the allantois now before the Society; and Mr. Costs 

 having expressed some doubts respecting my determination of the two ap- 

 pended sacs, we together dissected the foetus, and found that the vessels ra- 

 mifying on the larger sac, which 1 had before described as the umbihcal 

 vesicle, had the usual disposition and connections within the abdomen of 

 omphalo-mesenteric trunks, corresponding with the figure above-cited in the 

 Philosophical Transactions, and that the allantois was contin\ied from an 

 urachus, such as is represented in figs. 6, 7 and 8, pi. VII., Philos. Trans., 

 1834." 



