ADDITIONS TO THE LIST OF DIATOMACEJE. Ill 



The rock pools at Filey have also proved a good 

 collecting ground, yielding amongst large quantities of 

 Fragilaria striatula, such interesting forms as Amphora 

 inflexa and Thalassionema nitzschioides — both rather anom- 

 alous and troublesome to classify. Van Heurck includes the 

 former under Amphora on the authority of Cleve, reserving 

 his own opinion, and Peragallo, who describes the genus 

 Amphora as " actuellement le cauchemar (nightmare) du 

 diatomiste," follows suit, with evidently some doubt, since 

 he gives almost equal honour to the old specific name 

 Okedenia, which was given to it by Eulenstein in honour of 

 Okeden, an English diatomist, contemporary and correspon- 

 dent of Norman. 



Thalassionema nitzschioides is the name approved by 

 Peragallo for the latter, and Van Heurck, while retaining it 

 among the Synedras, says "It is not a true Synedra. 

 Perhaps a new genus should be created for it." 



The inland waters have been so well worked by Norman 

 and others, that many new discoveries can hardly be 

 expected. Pinnnlaria sublinearis, which I record here for 

 the first time in this district, was, 1 have no doubt, 

 frequently found by Norman, as I observe in looking through 

 his note-book, he two or three times mentions having noticed 

 a Pinnularia "like P. viridis, but with finer striae," which is 

 an exact description of this form. Pinnularia Hilseana, 

 which I found in a ditch in Houghton Wood, is a small but 

 beautiful form of infrequent occurrence. 



Perhaps my most interesting find was taken from a ditch 

 in the low-lying country between the Wolds and the Market 

 Weighton Canal, described on the map as Hotham Carrs. 

 This gathering consisted largely of a beautiful form of 

 Surirella, figured and described in Peragallo's " Diatomees 

 Marines de France " as Surirella medulica Per. It appears 

 to be a variety of S. conslricta WSm. (S. Smithii Ralfs.), 

 distinguished from the type form by its straighter sides. 

 Peragallo records this variety as found by him in brackish 

 water at Medoc, a place in the south of France well known 

 to claret drinkers. 



Van Heurck states that Surirella Smithii is recorded fo 

 brackish waters in England by Wm. Smith, Comber ana 

 Stolt, and in Ireland by Q'Meara. No previous freshwater 

 records appear to be known, yet here we find it abundantly 

 in a ditch about five miles from the Humber, and in country 

 that has not been overflowed by the tide for at least a cen- 

 tury. It should, however, be noted that the Jurassic rocks 



