A. DE BREBISSON ON SOME FRENCH DIATOMACE^. 7 



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

 his P. acrosphceria 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. 



u 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. 



il 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. 



" 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. 



Fig. 1. Surirella Capronii— the form found at Shere by Dr. Capron X 300 



diameters. 

 Fig. 2. Surirella Capronii — as found by M. de Brebisson at Falaise X 300 



diameters. 

 Fig. 3. Longitudinal section of valve of the same species X 300 diameters. 

 Fig. 4. Navicula punctata X 600 diameters. 

 Fig. 5. Navicula oculata X 600 diameters. 

 Fig. 6. Cyclotella rectangula X 600 diameters. 

 Fig. 7- Epithemia succincta X 600 diameters. 

 Fig. 8. Peronia erinacea X 600 diameters. 



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



