274 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



group of plants now under consideration a similar course 

 must be followed. For instance, I take a gathering of 

 Algae from a ditch or pond, keep it in a vessel, and from 

 time to time examine it. If the gathering happens to be 

 mixed, I shall find perhaps that the reproductive bodies 

 proceeding from two or three different Algse are similar in 

 size, form, &c. ; now deductions made from the course of 

 events that follow are very liable to error, and at all events 

 as a matter of science, would be open to doubt. The 

 following case will illustrate my meaning even more 

 strongly. Quite recently I gathered from a dripping 

 sandstone rock at Storeton quarries some jelly-looking 

 material which I thought at the time might be some of 

 the Nostoceae. Placing it under the microscope I made 

 out the following forms, Gloeocystis rupestris, Lyng,, 

 Gloeocapsa arenaria, Eabh., Gloeocapsa quatemata, Breb., 

 Palmella mooreana, Harv. Here we have three genera 

 and four species, composed of similar pseudocysts, all 

 existing together in a gelatinous matrix. Is there any 

 connection between them? Is there genetic affinity? 

 Are any of these forms but stages in the life history of 

 either these or higher forms of Algse ? It is generally 

 admitted that Gloeocapsa is analogous to Gloeocystis in the 

 two divisions, the chlorophyll-green and the blue-green 

 divisions of the Algae, and Eichter goes so far as to suggest 

 there is identity. It must be clear that nothing short of 

 separation and pure cultivation of these several forms can 

 give us the solution to these questions. When we are 

 able to accurately trace the development of many so-called 

 unicellular Algae, I have no doubt that the classification 

 of the Fresh Water Algae will be very much simplified. 



The question of classification is always a difficulty, but 

 as I have worked chiefly with Dr. M. C. Cooke's British 

 Fresh Water Algae, in the main I have followed the 



