132 



HARDWICKE'S SCIENCE-GOSSIP. 



[June 1, 186S. 



in the Lough Mourne deposit, and at Hickling, 

 Norfolk. 



Pinnularia acuta (Smith). This species will be 

 easily detected in the median densities. 



Pinnularia viridis (Smith), a curiously distorted 

 form, is not uncommon in this material, and affords 

 a valuable illustration of the repetition of an acci- 

 dental distortion by self-division ; the distortion to 

 which I allude is a sudden constriction of the valve 

 on one side only. 



Fig. 129. 

 Navicula scutelioides x S00. 



Fig. 129. 

 Navicula cocconeiformis x 400. 



Fig. 127. Navicula Americana x 400. 



Pinnularia isocephala (Ehr.) Valve linear, with 

 three sub-equal inflations; ends somewhat deeply 

 constricted and capitate, stria; distinct, radiant, 

 not reaching median line, interrupted for some 

 distance opposite the central nodule (fig. 130, x 400). 

 This form Las the undulations less distinct, and the 

 ends more conspicuously capitate, than Pinnularia 

 nodosa. 



Stauroneis Baileyii, S. Phcenicenteron, S. anceps, 

 and S. gracilis occur in this material. 



Stauroneis (n. sp.) Valve minute, linear ends 

 suddenly contracted and apiculate, stauros narrow, 

 linear, not reaching the margin, stria? distinct, 

 about 50 in '001 (fig. 131). This curious little form 

 is by no means rare in the lightest densities of this 

 deposit. 



Fig. 131. 

 Stauroneis (n. s.) x 1000. 



Fig. 130. Pinnularia isocephala x 400. 



Surirella Craticula (Ehr.) This form occurs but 

 rarely, and although a widely distributed species, 

 has never been found in any quantity. It has been 

 suggested by several observers that it is an ab- 

 normal state of some species of Navicula. Mr. 



Norman, in his " List of Diatomaceae occurring in 

 the Neighbourhood of Hull," published 1865, says : 

 " This is certainly wrongly referred to Surirella ; 

 it has a distinct central nodule, and hence it must be 

 removed to Navicula; and in all probability is a state 

 of N. cuspidata." In a gathering from New Zealand 

 it occurs with the outline of Navicula ambigua. 



Surirella elegans (Ehr.) Valve oval and elliptical, 

 alse distinct, canal iculi delicate, 5 to 6 in '001', be- 

 coming indistinct as they approach the centre. 

 This species was only known to Ehrenberg by the 

 fragment figured by him. The author of the 

 Synopsis seems to have overlooked or confounded 

 it with Surirella nobilis. It occurs in several foreign 



Fig. 132. Surirella elegans x 400. 



and British deposits, and in recent gatherings from 

 Scotter Common, Market Weighton Canal, Hull, 

 and Devizes ; in my slide from the last-mentioned 

 locality it is very plentiful and fine ; in the Perley's 

 Meadow deposit it occurs but sparingly, and differs 

 slightly from the species found in the above-named 

 localities. The canaliculi are somewhat closer, and 

 reach a narrow, well-defined, lanceolate blank space 

 (fig. 132, x 400).* 



Surirella cardinalis (n. sp.— F. Kitton). Valve 

 broadly ovate, aire distinct, canaliculi marginal, 

 absent from the top of the valve 6 to 7 in "001, 

 central portion of valve faintly granulate (fig. 133, 

 x 400). It is not without some misgivings that I 

 make the above a new species ; it may possibly be 

 only a variety of S. elegans, but the short canaliculi 



* The lanceolate space is too distinct in the figure. 



