A. DE BREBISSON ON SOME FRENCH DIATOMACEJ3. 43 



Wales, agreeing exactly with Smith's in his slide in the Brit. Mas. ; 

 his P. acrospharia turns out to be the longer form of the same seen 

 also here, but most common in the Premnay peat.' I am afraid that 

 the spines of Surirella Capronii are of no scientific value, and if 

 not this form must be referred to S. splendida. 



" Eupodiscus Gregorianus is the Eupodiscus subtilis of Gregory. 

 It is not a true Eupodiscus, but one of the forms of Actinocyclus 

 Ehr. ; the marginal spines are not peculiar to this genus, and are 

 of no generic or specific value ; they may be observed in other 

 genera, notably in Cyclotella rotula. This form is not the same as 

 Coscinodiscus concinnus of Smith, which is a true Coscinodiscus, 

 with delicate hexagonal cellules. It is common in the stomachs of 

 Noctiluca. 



tl E. Roperiana is identical with Coscinodiscus ovalis. My re- 

 marks on the preceding species apply to this form. It seems to 

 me to belong to the genus Actinocyclus rather than Eupodiscus or 

 Coscinodiscus. 



11 One of the slides marked for Eupodiscus Gregorianus does not 

 contain that form, but is the same as the Navicula punctata slide. 

 I enclose a slide of Navicula punctata (from the Premnay peat) 

 for the Club. 



" F. KlTTON." 



Plate I. 



Surirella Capronii— the form found at Shere by Dr. Capron X 300 



diameters. 

 Surirella Capronii — as found by M. de Brebisson at Falaise X 300 



diameters. 

 Longitudinal section of valve of the same species X 300 diameters. 

 Navicula punctata X 600 diameters. 

 Navicula oculata X 600 diameters. 

 Cyclotella rectangula X 600 diameters. 

 Epitliernia succincta X 600 diameters. 

 Peronia erinacea X 600 diameters. 



All the above figures drawn from the slides by H. F. Hailes, V.P. 



