620 B. ETHERIDGE ON THE PALEONTOLOGY OP THE 



Silurian), and Prof. H. A. Nicholson a specimen, showing the cells, 

 from the Hamilton group (Upper Devonian). The condition of the 

 example in Capt. Feilden's collection does not enable me to add any 

 further details. 



Log. Feilden Isthmus, lat. 82° 43'. 



Fenestella, sp. 



Obs. Amongst some finely preserved remains on the surface of a 

 piece of limestone, two small fragments occur which bear a close 

 resemblance to a species I described from the Scotch Carboniferous 

 limestone as Fenestella bicellulata*. The essential characters are 

 the oblong fenestrules, alternate in contiguous series, with two cells 

 only to every fenestrule on each side the angular interstice, placed 

 in the angles formed by the junction of the interstices and dissepi- 

 ments. These characters are as strongly marked in the Arctic as in 

 the Scotch examples ; but the marked indentation of the sides of the 

 fenestrules by the aperture of the cells, and the strong median keel, 

 with its line of nodes visible in F. bicellulata, do not appear to be 

 present in the Arctic form. Furthermore, the prominent mouths of 

 the cells are also absent in the latter. A comparison may also be 

 instituted with Polypora intermedia, Prout f (which, I think, should 

 perhaps be more properly regarded as a Fenestella) ; but the frag- 

 ments are small, and the preservation not all that could be desired, so 

 that we can do little more than give a mere notice of such a form, 

 to be used in future investigations. It must not be forgotten that 

 Mr. Salter mentions the occurrence of a Fenestella, with only two 

 cells in the length of the fenestrule, in Dr. Sutherland's collection. 



Log. Feilden Isthmus, lat. 82° 43'. 



Fenestella, sp. 



Obs. A specimen of a Fenestella with a fan-shaped polyzoarium 

 has been split in two in a longitudinal direction; and as the external 

 characters are not shown, specific determination is quite out of the 

 question. The interstices and dissepiments were arranged in a very 

 regular and definite manner ; the former straight, narrow, and seldom 

 bifurcating, the latter short and thin. The fenestrules enclosed by 

 them are long and narrow, and the whole appearance of the poly- 

 zoarium recalls to us that of F.plebeia, M'CoyJ, of our own Car- 

 boniferous rocks. The cells were, so far as I can make out, from 

 four to six in the length of a fenestrule ; in fact the whole aspect is 

 that of F. plebeia. Had the cells been less in number it might also 

 have been compared with F. membranacea, Phill.§ 



Log. Feilden Isthmus, lat. 82° 43'. 



* Mem. Geol. Sury. Scotl. Explanation-sheet 23, 1874. 



t Trans. St. Louis Acad. i. p. 272, 1. 15. f. 5. 



| Synop. Carb. Foss. Ireland, 1844, t. 29. f. 3. 



§ Synop. Carb. Foss. Ireland, 1844, p. 202 (M'Coy's description). 



