CHIEFLY IN NOKTHUMBERLAND AND DURHAM. 363 



SclerocMlus gracilis, Brady and Robertson. Ann. and 

 Mag. Nat. Hist., Ser. 4, Vol. HI. (1869). Plate XX., 

 figs. 11, 12. 



The species described by Mr. Robertson and myself under the 

 name SclerocMlus gracilis, was not recognized by us as being 

 identical with the P. Fischeri of Sars. Indeed we had supposed 

 it to belong, as our name indicates, to a different genus, arriving 

 at this conclusion from a consideration of the form of the shell. 

 The animal itself we had no opportunity of examining ; but none 

 of our specimens exhibited the beautiful dark coloured arbores- 

 cent or dendritic markings so characteristic of the genus Para- 

 doxostoma. The figures now given represent both male and 

 female shells. 



Paradoxostoma pulchellum, G. 0. Sars. Plate XII., figs. 4, 5. 



The male of this species has not previously been observed, 

 but I presume, from the rather elongated form of the carapace, 

 that the specimen here figured belongs to that sex. 



FULWELL. 



This gathering was taken from the almost dried-up bed of 

 some ornamental water through which a small stream usually 

 runs. The water had been let off previous to my visit, and all 

 my captures were made in a small pool about two or three inches 

 deep, which had been accidentally left behind. My impression 

 is that even this spot had not long before been quite dry, as the 

 mud brought up was (much of it) a good deal caked. My object 

 in going to this spot was to obtain specimens of Potamocypi-is 

 fulva, which I thought I remembered having seen in gather- 

 ings previously obtained there, but which I did not at the time 

 thoroughly recognize as distinct from Cyj)ridopsis villosa. These 

 earlier specimens were indeed recorded in my "Monograph" 

 under the latter name, but as I now believe erroneously. I well 

 remember the difficulty I felt in forming a judgment as to their 

 specific character, and I was probably deterred from describing 

 them as a new species by the fear of unnecessarily multiplying 



