22 P. KITTON ON SOME NEW DIATOMACEiG. 



elevation like a reversed V (\), the top of which constitutes the 

 pseudo raphe. 



Sceptroneis ? claws, n. sp., F. K. Valve cuneate, superior apex 

 broad, rapidly diminishing to half its breadth, afterwards tapering 

 gradually to the rounded inferior apex. Proceeding from the 

 margins of the superior apex are nine longitudinal folds, gradually 

 diminishing in length as they approach the sides; the raphe becomes 

 forked a little below the three longest folds which it embraces. 

 Strise moniliform, about 28 in '001" ; length, *01 ; breadth of 

 superior apex, '0016, do. inferior, "0006. " Challenger" dredging. 

 — PI. IV., Fig. 6, b-a, superior apex. 



I, at one time, thought this form might be an abnormal state of 

 some species of Synedra or Sceptroneis, but having found several 

 fragments all resembling the perfect specimen from which the 

 illustration was made, I have come to the conclusion that it is a new 

 species if not a new genus. In outline it very much resembles a 

 horse-shoe nail. 



Navicula Lyra, abnormal. Valve with one end broadly rounded, 

 the other produced and mammiform ; raphe imperfect, obsolete on 

 the upper half of the valve, the smooth, lyrate spaces on each side 

 of the raphe in the normal form are here represented by a horse-shoe 

 shaped hyaline band, commencing a little above the central nodules, 

 and terminating near the mammiform apex. Strias moniliform, 

 radiant on the upper half and sometimes confluent, having the 

 appearance of radiating costee, not reaching the margin of the 

 rounded end. Length, -0042 ; breadth at centre, '0020 ; broad 

 apex, -0009 ; narrow apex, -0003. In a gathering from Pensacola, 

 Gulf of Mexico, sent to me by A. W. Griffin, Esq., of Bath. 



This form very much resembles in outline two abormal forms of 

 Navicula ( Stauroneis) maculata, of which Herr Weissflog has kindly 

 sent me photographs. In both specimens the striaa on the upper 

 portion do not reach the margin of the broad end. In one specimen 

 an irregular smooth space surrounded the central nodule, and a slight 

 trace of raphe exists near the small apex ; length, -0048" ; breadth 

 at centre, "0023". In the second specimen a circular sub-central 

 smooth area is visible, the terminal nodules lying just within its 

 circumference. The lower half of the raphe is normal, but that of 

 the upper part is nearly at right angles with it. Length, -0043 ; 

 breadth, '0023. 



