172 Mr. G. Gulliver on the Red Blood-corpuscles of 



Dendeites. 



Very often, on old kerataceous fibre, little, colourless, cir- 

 cular dentritic spots make their appearance whose structure is 

 so minute that even under a compound power of ^ inch with 

 high ocular it does not appear satisfactorily. All that can 

 at present be stated of them is, that they are composed of 

 branched filaments which radiate from a central point ; but 

 whether they are algoid or fungoid, or what their real nature 

 is, future observation must determine. 



KOT. 



Lately several complaints have been made of the rapid 

 Avashing away of officinal sponges after they have begun to be 

 used ; and on microscopical examination of such sponges before 

 and after they have been brought into use, it would appear 

 that while the superficial fibre is all continuous, that within 

 is broken up into short pieces. How and when this occurs I 

 am unable to state, further than that, like dried fish not pro- 

 perly cured, the surface may remain good while the in- 

 terior becomes broken down by putrefaction ; or it may be 

 from some chemical substance used in preparing them for 

 sale, which has not been thoroughly washed out from the 

 interior ; but the surface remaining sound in each instance 

 would ensure their sale until the unfortuate purchaser finds 

 out that, after a little usage, they become reduced to nothing, 

 and that the soundness was merely superficial. Perhaps the 

 best test of a sound sponge is the extent to which it expands, 

 and vice versa, after having been filled with water. Those 

 which are broken down in the interior, not having the same 

 amount of resiliency as the rest, will probably vary little in 

 size by the change. (For an excellent account, with illustra- 

 tion, of the mode in which the officinal sponge is obtained in 

 the Levant, see ' Travels and Researches in Crete,' by Captain 

 {now Admiral) T. A. B. Spratt, R.N., C.B., F.R.S., &c., 

 vol. i. chap. XX. p. 215, 1865 : Van Voorst.) 



XIX. — Measurements of the Red Blood-corpuscles of the 

 American Manatee (Manatus americanus) a7id Beluga leucas. 

 By George Gulliver, B.A., Pemb. Coll. Oxon. 



Through the kindness of Mr. Carrington I have been enabled 

 to examine the blood of the American Manatee now in the 

 Royal Aquarium, and have made careful measurements and 

 comparisons of the red corpuscles. 



