INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC 141 



Volvox minor.* — One point left undecided in Cohn's otherwise 

 exhaustive researches on the life-history of Volvox was the mode of 

 germination of the oospores. This has now been observed by O, Kirch- 

 ner in the case of V. minor. In February the contents of the oospore 

 escape from the ruptured exospore in the form of a sphere, the endo- 

 spore at the same time swelling up greatly ; and are first divided by 

 two walls at right angles to one another. The four cells thus formed 

 separate from one another in such a way that they maintain their 

 connection only at the posterior end. This forms one pole of the 

 subsequently spherical cell-family, the other end closes up only after 

 a large number of cells have been formed. A new family is thus 

 directly derived from each oospore by the division, and the subsequent 

 peculiar mode of displacement of the cells. The distinction does not 

 appear to hold good which was previously considered to obtain between 

 V. glohator and V. minor, that the latter is dioecious ; the families 

 go through first of all a female and later a male condition, and are 

 therefore proterogynous. 



MICEOSCOPY. 



Professor Huxley on Work for Microscopists.f— In his presi- 

 dential address to the Quekett Microscopical Club, Professor Huxley 

 said that having been asked to indicate those courses of inquiry wliieh 

 might best be commended to members of such a Society, he thouglit 

 that what was desirable was " the following up of details, tracing out 

 minutiae of structure, and such questions as are only to be solved by 

 long and patient devotion of time and dexterity, and a thorough 

 knowledge of instrumental-manipulation — it is exactly there that men 

 of science find their difficulties, because the amount of time consumed 

 is so great. 



" Take, for example, the application of persistent watching 

 to the unravelment of the life-history of a vast number of low 

 organisms ; that is a process which has been adopted in respect to 

 certain fungi in order to ascertain whether they are parasites or 

 variations. In such a case the plan pursued is that of taking the 

 spores and watching them step by step, and there is no other way of 

 doing it ; it involves enormous expenditure of time and great instru- 

 mental dexterity, but those who can follow it obtain results which are 

 to be obtained in no other way. The work of Mr. Dallingcr and 

 Dr. Drysdale, for instance, affords us a very remarkable example of 

 this kind of observation. Tliese two gentlemen mounted guard alter- 

 nately over a Microscope for days and days, and watched one identical 

 monad through all its stages ; and they succeeded in tracing out its 

 entire life-history, and made an epocli in our knowledge of these lowest 

 forms. Now suppose this kind of observation was to be directed to 

 the Infusoria in general, wliat an ojiportunity tliero is for some of 

 you ! There is not a single genus or species of which we may say 

 that wo know the whole history. The common Paramecium, for 



» Cohn, 'Beitr. Biol. Pflaiizen,' iii. ; see 'Bot. Ziit.,' xxxvii. (1879) p. 61>3. 

 t ' Jourri. Qnek. Micr. Club,' v. (1879) p. 250. 



