11)1)0] MICROSCOPICAL JOURNAL. 273 



Hyalodiscus subtilis was founded by Bailey in his Notes 

 on new species and localities of microscopic organisms, 

 Washington, 1858 page 10, fig. 12. The figure is a good 

 one for the time and, as I have said, was engraved on steel 

 by John E. Gavit, my friend and successor in the presi- 

 dency of the American Microscopical Society. It is Hy- 

 alodiocus scoticus, A. Gr. and californicus, J. W. B. and 

 Cyclotella scotica, F. T. K. from the coast of Scotland 

 and on the English coast, where it is small. The large form, 

 which is essentially Hyalodiscus subtilis, has never been 

 seen, or at least published, there. It is not found in the 

 phytoplankton of the Atlantic and its tributaries, a treatise 

 on which I am indebted to Prof. P. T. Cleve for. In fact 

 the phytoplankton seems to be free forms and Hyalodis- 

 cus, and Trochiscia of course, are fixed forms. Hyalo- 

 discus subtilis was called Craspedodiscus franklinii by 

 Ehrenberg. And we can see by comparing the figures of 

 Craspedodiscus coscinodiscus, C. Gr. E. with that of Hy- 

 alodiscus subtilis, J. W. B. which are given both in plate 

 V. of Prit chard's Infusoria, Ed. 1861, that they are alike. 

 But Craspedodiscus coscinodiscus is a fossil form and we 

 do not know how it grows or grew attached to submerged 

 substances as Trochiscia moniliformis does, or as Hyalo- 

 discus also does now. In fact this is but another exam 

 pie of the danger of describing "species" from fossil 

 forms. Suffice it to say Hyalodiscus subtilis, or what- 

 ever we may call it, is extremely common in the living 

 state %s the Alaskan gatherings show. 



Anotherrecord which I have to make is of Biddulphia 

 laBvis, C. Gr. E. and is of the following. And I find it in 

 rHj notes of microscopic and other observations made since 

 A >ril 26, 1862, and kept in a book along with illustrations, 

 colored or not, is that on the 18th of January 1890, I made 

 a collection of Bacillaria on the road from Elizabeth to 

 Nov ark, in fresh water, that Biddulphia turgida, C. Gr. E. 

 s a var. of Biddulphia lasvis, C. G. E. and I remember 



