255 



hearty welcome. This the meeting accorded, and Mr. Wenham 

 duly acknowledged. 



With reference to the paper by Mr. A. A. 0. Eliot Merlin 

 on Navicula Smithii read at the last meeting, the Hon. Secretary 

 showed by a blackboard drawing the arrangement of the fine 

 structure which Mr. Merlin had discovered. This, in his 

 opinion, illustrated in a most perfect and complete manner the 

 well-known views of Mr. Nelson as to the development of diatom 

 structure. 



Mr. D. J. Scourfield, F.Z.S., F.R.M.S., gave a short account 

 of a valuable paper on " Philodina macrostyla, Ehr., and its 

 Allies," communicated by Mr. James Murray. The genus 

 Philodina was founded by Ehrenberg in 1830. His order 

 Zygotrocha, including all Rotifers having the ciliary wreath 

 divided into two parts, contains an illoricated family, Philo- 

 dineae, which corresponds in the main with the order Bdelloida, 

 as now understood. The presence of eye-spots, formerly held 

 to be critical, is not now insisted on, and Mr. Murray redefines 

 the genus as " Genus Philodina. — Toes, four ; eyes, cervical or 

 none." Mr. Scourfield then proceeded to refer to the changes, 

 which are very few, which this definition will make in the 

 personnel of the genus. He also mentioned that Mr. Bryce 

 quite agreed with the alteration. The genus now includes some 

 twenty-six admitted species, of which sixteen have eye-spots. As 

 these species may be conveniently arranged in five groups, it was 

 suggested that further investigation might prove the generic 

 definition still too wide. Mr. Scourfield instanced Cyclops, with 

 its twenty-five or more British species, as a similar case, and 

 said that unless the genus was broken up into groups it was 

 almost impossible to satisfactorily comprehend it. Mr. Murray's 

 paper proceeded to deal with the characteristics of the five groups 

 proposed. 



Mr. D. Bryce, after some appreciative remarks on the paper, 

 said that as long ago as 1886 Mr. Milne, of Glasgow, said that 

 the eye-spots could no longer be considered as a critical point 

 in the classification of the Bdelloid Rotifers. He also referred 

 to the chief differences between the genera Rotifer and Philodina. 

 As contrasted with the sixteen species described by Hudson and 

 Gosse, Mr. Bryce said he knew at least a hundred, and there 

 were perhaps fifty more known to other investigators. 



Journ. Q. M. C., Series II.— No. 62 19 



