37' 



Yorkshire Naturalists at Bowes. 



found at all in Sleig-htholme Beck, and the first was only repre- 

 sented by a few small-sized specimens. On the other hand, the 

 principal forms in Sleig-htholme Beck were Diatoma hyemale, 

 Amphora ovalis, and Amphipleura pellucida, none of which were 

 found at all in Deepdale. Of 37 species recorded for Deepdale 

 and 24 for Sleig-htholme, 13 only were common to the two 

 streams, and, with the exception of the ubiquitous Naviciila 

 radiosa and Eficyonema ventricosuni, none of these were very 

 abundant in either. The explanation of this curious divergence 

 is to seek, and is not very obvious. A complete list follows : — 



Deepdale Beck : — 



Achnanthes linearis. 



Cymbella affinis. 



C. obtusa. 



Denticula tenuis. 



Diatoma elong-atum var. tenue. 



Encyonema gracile. 



E. tiirg'idum. 



E. csespitosum. 



Eunotia lunaris. 



Gomphonema acuminatum. 



G. montanum. 



G. parvulum. 



Nitzschia commutata. 



Sleig-htholme Beck : — 

 Amphipleura pellucida. 

 Amphora ovalis. 

 Cymatopleura elliptica.. 

 C. Solea. 



Diatoma hyemale. 

 Epithemia sorex. 



Common to the two streams 



Cocconeis pediculus. 



C. placentula. 



Cymbella affinis. 



C. cistula. 



C. cymbitbrmis. 



Encyonema ventricosum. 



Epithemia gfibba. 



E. zebra. 



Nitzschia linearis. 

 N. vitrea forma major. 

 Pinnularia mesolepta. 

 Pleurosig-ma Spencerii. 

 Rhoicosphenia curvata. 

 Surirella ovalis vars. Crumena 



and minuta. 

 Stauroneis anceps. 

 Synedra radians. 

 S. pulchella. 

 Tabellaria flocculosa. 

 Vanheurckia vulg^ari^. 



Epithemia turg-ida. 

 Eunotia pectinalis. 

 Navicula elliptica. 

 Pinnularia sublinearis. 

 P. viridis. 



Eunotia arcus. 

 Gomphonema constrictum. 

 Meridion circulare. 

 Navicula radiosa. 

 Synedra ulna and vars. lan- 



ceolata, long-issima, and 



splendens. 



In tank at end of Bowes villag-e, near the house said to be the 

 prototype of Dickens' Dotheboys Hall : — 



Frajj-ilaria virescens. Synedra Vaucherise. 



F. capucina. Tabellaria fenestrata. 



Synedra ulna var. obtusa. 



And a few others previously recorded in the becks. 



Naturalist, 



