JOURNAL OF MICROSCOPICAL SCIENCE. 



DESCRIPTION OF PLATE I. 



Illustrating Professor Gregory's paper on some new species 

 of British Diatomaceae. 



N. B. — Most of the figures in this Plate liave not been drawn to tlie 

 scale now usually adopted, of 400 diameters, but to a scale considerably 

 smaller, which, according to my estimation, does not much exceed 300 

 diameters. This remark applies particularly to the larger forms, such as 

 figs. 4, 5, 6, 7, 11, 28, 38. The reader is requested to bear this in mind, 

 when comparing these figures with those of the Synopsis of the Rev. 

 Professor Smith. As for the smaller forms, they generally vary so much 

 in size that the figures may be held to represent average individuals under 

 a power of rather less than 400 diameters. 



I. Species new to Britain . 



Fig. 



1. — Eunotia tridentula, Ehr. 

 2. — Navicula Trochus, Ehr. 

 3. — „ dubia, Kutz. 

 4. — „ Bacillum, Elir. 



(qu. N, Americana, Ehr. ?) 

 5.— Navicula (Pinnularia) nodosa, 



KUtz. 

 6. — Pinnularia megaloptera, Ehr. 



Fig. 



(P. pachyptera, Ehr. ? 



lata, Sm., var. ?) 



7. — Pinnularia dactylus, Ehr. 



8. — ,, pygm;ea, Ehr. 



9. — Stauroneis Legumen, Kiitz. 



10. — „ veutricosa, Kiitz 



11. — Cocconema cornutum, Ehr. 



12. — Gomphonema subtile, Ehr. 



II. Neio Species, named by other writers, hut not yet figured. 



] 3. — Navicula apiculata, Sm. 

 14. — „ rostrata, Sm. 



15. — Navicula scutelloides, Sm. 

 16. — Mastogloia Grevillii, Sm. 



III. Neio Species, noio first named. 



-Pinnularia Elginensis, W. G. 



,, globiceps, W. G. 

 -Stauroneis obliqua, W. G. 

 — „ „ with sigmoid 



median line. 

 -Stauroneis (?) ovalis, W. G, 



dubia, W. G. 

 -Surirella tenera, W. G. 



This form frequently occurs 



twice as large as the 



figure, but with the 



same proportions. 



-Gomphonema insigne, W. G. 



Side view. 



h. Front view. 

 ,, ventricosum,W. G. 

 ,, jrqualc, W. G. 

 „ SarcophaguSjW. 0. 

 h. Front view. 



