HICK : KLEIN ON IHE GENUS VOLVOX. 91 



occur in these three groups of alternating generations he does not 

 enter, regarding them as exceptional ; but he emphasises the fact that 

 sexual activity is uninterrupted from March to November. 



With regard to Volvox g/obafor, his own observations and those 

 of others, lead Klein to the conclusion that this species also probably 

 possesses more complicated sexual relationships than is generally 

 supposed, and these seem to be connected in some way with the 

 time of the year. He observed oospores in May and June, 

 Falkenberg at the end of June, Stein in August, and Cohn, as well 

 as Klein himself, in October and November. It would seem, too, 

 that the moncecism of this species is occasionally lost, and that 

 colonies occasionally become proterandrous, and others perhaps 

 proterogynous. Other departures from the usual development are 

 also mentioned, but these need not detain us, and we will only add 

 that asexual and sexual colonies planted by Klein in May remained 

 sterile during the whole summer, and only formed the second 

 generation of oogonia at the beginning of November. 



Reflecting on the facts adduced by Klein on the points dealt 

 with in the preceding paragraphs, I have been impressed with the 

 smallness and indefiniteness of the knowledge we possess of the 

 biology of the British forms of Volvox, as also with the fact that 

 English writers seldom distinguish the species met with. In the 

 course of my own experience I have seldom gathered the true 

 Volvox globator as now defined by Klein, and most of the speci- 

 mens gathered by others that have come under my notice have been 

 Volvox aureus. Moreover, so far as I am aware, little attention has 

 been paid in this country to the seasonal succession and duration of 

 the various colonies and generations, and the physical and meteoro- 

 logical conditions under which they occur. This being so, may 

 I suggest to the botanical readers of 'The Naturalist' the desirability 

 of collecting data with a view to extending our knowledge on these 

 matters? I have myself taken up the subject in the district round 

 Manchester, and have already obtained valuable assistance in the 

 work. As, however, the observations cannot be too widely spread, 

 either personally or territorially, it would be an advantage to have 

 the co-operation of Yorkshire botanists, so that the results which we 

 may hope to obtain may be applicable to the two great counties of 

 Yorkshire and Lancashire, if not to a still wider area. Though 

 hardly necessary, it may be well to add that those who act upon the 

 above suggestion should note, among other details, the species of 

 Volvox they collect, the associated flora and fauna, the nature, 

 surroundings, and elevation of the pond, and the state of the 

 weather, wind, etc., at the time of collection. 



]March 1890. 



