BRITISH DIATOMACE.E. 60 



Hardly distinct from the last, with which it often occurs intermingled : 

 the greater number of loculi is perhaps its only important character. 



Plate LIV. 340. 



3. Mastogloia Smithii, Thw. Valve elliptical, extremities pro- 

 duced; loculi 6 to 24; striae 42 in -001". Breadth of valve -000.V 

 to -0008". v.v. 



/3. Extremities produced and inflated. 



Mastogloia Smithii, Thw. in lit. Oct. 1848. Navicula biscalaris, Breb. in 

 lit. Jan. 1853. Frustulia elliptica, Ag. ad spec, in herb. Grev. ? 



Fresh or brackish water. " Little Sea," Dorsetshire, Oct. 1848, May 1849 

 and Sept. 1851 ; Lewes, Oct. 1851 ; Ballycottin Marsh, Co. Cork, May 1855; 

 Lough Derg, Co. Clare, Julyl855, W.Sm. Cumbrae, Sept. 18 54, Mr. Hennedy. 

 Lough Leven, Aug. 1855, Br. Gregory. New North River, Dublin, 1852, 

 Mr. Shadbolt. Lough Skaill, Orkney, Aug. 1855, Rev. J. Pollexfen. 



Its freshwater habitat, distinctly produced and occasionally capitate ex- 

 tremities and variable breadth, distinguish the present species ; but as it some- 

 times intrudes upon the localities of the species previously described, it 

 may be readily confounded with them. I refer doubtfully to Agardh's 

 gathering, as it was manifestly impure, containing abundance of the present 

 species, but also, mixed with it and many freshwater forms, several species ex- 

 clusively marine. The medley was such as does not naturally occur even in a 

 brackish water locality, and contained so many forms, that the one intended by 

 the inscription could not be satisfactorily ascertained. 



Plate LIV. 341. 



4. Mastogloia apiculata, n. sp. Valve lanceolate-elliptical, extre- 

 mities slightly produced, and obtuse ; loculi 30 to 50; striae 42 in 

 •001". Length of frustule -0016" to -0032". Breadth about 

 •0008". v.v. 



Marine. Salt Pans, Hampshire, July 1854, W.Sm. Donaghadee, Aug. 

 1854, Mr. Hennedy. 



A very distinct species, to which perhaps Ceratoneis laminaris of Kiitzing 

 ought to be referred ; but the figures in the ' Bacillarien,' xxx. 37, are not 

 sufficient to enable me to decide this point. 



Supp. Plate LXII. 387. 



5. Mastogloia Grevillii, n. sp. Valve linear, cuneate towards the 

 obtuse extremities; loculi 15 to 20; striae moniliform, 24 in -001". 

 Length of frustule -0013" to *0022". Breadth of valve 0004". v.s. 



Greg. Mic. Journ. vol. iv. pi. i. 16. 



VOL. II. P 



