NOTES AND OBSERVATIONS ON BOARD H.M.S. RATTLESNAKE 9^ 



From Mr. Carter's account it would appear that when the " seed- 

 like body" germinates its cells burst, and their granular contents 

 become mixed. Subsequently protean cells, like the ordinary sponge- 

 cells, make their appearance /are'/^jj?^ with the disappearance of the 

 granules. 



Supposing this account to be correct, the conjugation in Spongilla 

 would be perfectly analogous to that of the Desmidije and Diatomaceje, 

 while in the Infusoria and Gregarinida; it would resemble that of 

 Zygnema. 



Generalizing the above details (full authority for which may be 

 found in the appended list of works), we may say that with the excep- 

 tion of the Foraminifera, about whose reproductive processes nothing 

 is as yet known, the Protozoa all reproduce their kind by a process of 

 endogenous development which is accompanied by greater or less 

 changes in the structure and powers of the reproducing cell. We may 

 add that in many cases these changed cells have been observed to 

 conjugate, previous to the occurrence of the endogenous development. 



Bearing all these facts in mind, let us return to Thalassicolla 

 nudeata. If the Th. punctata answer to a mass of sponge-cells, or an 

 aggregation of Gregarince, is it not possible that the Th. nudeata may 

 answer to the altered reproductive cell ? I have shown that the Th.. 

 nudeata may very possibly be nothing more than a separated and en- 

 larged cell of Th. punctata, and this possibility upon structural grounds 

 becomes, I think, converted into probabilit}', if Th. nudeata be compared 

 with Actinophrys Sol, which there is every reason to believe is the 

 reproductive stage of one of the Vorticellinae. 



Actinophrys Sol is a spherical gelatinous mass consisting of an 

 internal dark granular portion and a clearer external zone from which 

 many radiating threads are given off. Vacuolae are scattered through 

 the substance, larger in the external zone, smaller and more irregular 

 in the interior. 



If the animal is much compressed, nuclei and nucleated cells are- 

 forced out from its interior. 



Finally, two specimens of Actinophrys have been observed to fuse 

 together and become one. 



It is unnecessary to point out the perfect analogy between Actino- 

 phrys and Thalassicolla nudeata, with one exception, that the large 

 internal cell was not observed in Actinophrys — a circumstance which 

 might readily occur if it were delicate, even though it existed. 



The argument derived from this analogy becomes still more 

 strengthened if we turn to the excellent account of Noctiluca—s.- 

 marine phosphorescent body which has long been a zoological puzzle 



