298 Tra?isactions. — Botany. 



The usual modes of multiplication of the Diatomacece are stated to be 

 either division or conjugation. Facke however suspected, though he did 

 not actually observe, a formation of spores or gonidia such as are found in 

 many of the filamentous Confervoids. This method of reproduction I 

 beheve I have seen in Synedra ulna. In the autumn of last year I found, 

 amongst a growth of SpirogyrcB and Oscillatorm, a number of unusually 

 large specimens of Synedra, some of such magnitude as to be visible to 

 the naked eye. They were active, and evidently in a state of vigorous 

 growth. 



In fig. 12 I have endeavoured to depict the various stages of sporidial 

 growth : a shows a full-grown Synedra with the endochrome diffused through- 

 out the frond ; at h the endochrome is beginning to gather itself into a 

 distinct mass; at c it has divided, and a portion is attached to each of the frus- 

 tules, and a division into definite masses is commencing; at d this division 

 is complete, the masses forming lenticular bodies; at e they have moved into 

 pairs, so that their convex surfaces are in contact; in the next stage (/) each 

 pair has united and formed an elliptical spore ; at g the frustule has been 

 ruptured, and the spores are escaping. The escaped spores were evidently 

 held together by a hyaline substance, and exhibited the peculiar motion 

 termed swarming ; h, i, j, show different stages of growth of the young 

 Synedra^,, until, at k, a perfect siliceous deposit has been formed, and the 

 young Diatom is ready to recommence the whole process so soon as its 

 endochrome is sufficiently mature. 



VOLVOCINE^. 



1. Protococcus viridis, M.Dic, 3. 



,, vulgare, 



2. HcEmatococcus sanguineus. 



,, hinalis. 



,, niuronim, H., Ixxxi. 



3. Volvox globator, M.DiG., B. 



4. Pandorina murorum, M.Dic, 45. 



H(zmatococcus. — I have had a colony of this protophyte in my possession 

 for two years. I first discovered it in a jar which happened to be standing 

 in the rain and was half filled with water. By keeping water continually 

 in the jar the supply of Hamatococcus has never failed. Mr. Hamilton, of 

 Petane, also brought me a sample in the wool of a sheep.* 



* See " Trans. N.Z. Inst.," vol. vii., art. Iv. 



