10 DR. GREGORY, ON SOME NEW SPECIES 



species. It seems to be distinguished by the character of its 

 striation from all similar forms yet described. JV. varians 

 sometimes takes nearly the same outline, but is at once known 

 by its conspicuous and highly radiate stri2e. Length about 

 •0013 inch. Striae about 30 in -001". 



34. Pinnularia glohicejjs. — This elegant little form occurs 

 not unfrequently in a very beautiful gathering from Norfolk, 

 the same in which I first noticed Cipnhella pisciculiis. I have 

 met with it also, or at least a form much resembling it, in the 

 recent mud from the Dhu Loch in denshire. It is well 

 marked by its globular extremities and prettily curved outline, 

 swelling a little at the middle part. The terminal nodules 

 are very prominent, casting a shadow, the central are indefi- 

 nite. The striae are fine but sharp and distinct, not reaching 

 the median line. They have three centres of divergence, and 

 are entirely absent from a broad crucial space, like a large 

 false stauros, the upper and lower parts of which pass into the 

 long blank caused by the striae not reaching the median line. 

 In fact the arrangement of the striae and blank space is like 

 what we see in P. divergens, Sm. Towards the apices the 

 blank space expands again. Length -0014 inch. Striae from 

 36 to 40 in •001". It is possible that this form may be allied 

 to P. Stauroneiformis, or to P. divergens, as it is also possible 

 that the two last named may belong to one species. The name 

 must therefore be considered as provisional for the present. 

 In any case it must be distinguished as a striking and well- 

 marked form, even if only a variety. 



N.B, — Since writing the above I have observed, in some 

 gatherings from the neighbourhood of Duddingston Loch and 

 Arthur's Seat, as well as in some from the Bridge of Allan, 

 the latter made by Dr. Greville, and in one from Borthwick, 

 made by Dr. Balfour, a form apparently allied to P. cjhhiceps, 

 which for the present I shall call P. globiceps /3. It has a 

 much less elegant curve, but in most points agrees with the 

 form here described. 



35. Stauroneis ohliqria, W. G. — This very curious and well- 

 marked species has only occurred, as yet, in the gathering 

 from Lochleven, in which it is, though far from frequent, 

 always to be found, from 3 or 4 to 10 or 12 in a slide. In 

 form it is elliptico-lanceolate, usually rather short and broad, 

 sometimes longer. The stauros is broad and distinct, but less 

 so towards the margin, which, however, it reaches. The 

 striae are fine and slightly curved from the middle towards 

 the extremities ; but the most striking character is the peculiar 

 position of the median line, which does not, as usual, unite 

 the apices centrically, but has one of its ends on one side of 



