EEPOKT ON TIIE DIATOMACE^E. 33 



Navicula (?) jejuna, A. S. (Plate XX. fig. 12.) 



"We have here represented a frustule whose characteristics almost perfectly coincide 

 with those of the Java form figured in Schmidt's Atlas, Plate xlvi. fig. 7G. In the latter 

 the extremities, which are somewhat prolonged, are cuneately rotundate, while the ribs are 

 wide and transversely disposed in the middle but subradiating at the ends. In the present 

 case the outline is that of an ellipse of very great eccentricity, yet both forms must be 

 regarded as being specifically identical. 



Whether the generic name of Pinnularia or Navicula should be adopted must for the 

 present remain uncertain. 



Navicula (?) jejuna, A. S., var. nov. (Plate XXVIII. fig. 11.) 



The present figure represents a variety in which the shape of the valve and the 

 character of the striation for the most part agree with the typical species. The difference 

 observable in the central nodule may be explained by the fact that the nodule and raphe 

 are somewhat more raised than usual, and are accordingly seen in a lateral position. It 

 may also be distinguished from the typical frustule figured by A. Schmidt when viewed 

 in profile, being somewhat broader in proportion to its length. 



Navicula kerguelenensis, n. sp. (Plate XXVIII. fig. 16.) 



Parva, elliptica ; apicibus cuneato-rotundatis ; striis punctulatis subradiantibus ; areola 

 media subelliptica transversa. Ad insulam Kerguelen. 



This small naviculoid frustule was found in a collection of Diatoms from a soundino- 

 made near the island of Kerguelen. Its form is elliptical, and its extremities are cuneately 

 rotundate. The striae are fine and subradiating, while a subelliptical transverse areola 

 occupies the centre. No type hitherto recorded agrees with this form in its leading 

 characteristics, which has accordingly received a specific name indicative of the locality in 

 which it was obtained. 



Navicula lyra, Ehrenb., var. signata, A. S. (Plate XXX. fig. 13.) 



This figure represents an elliptical and elongated naviculoid frustule, in which the form 

 of the two bands that separate the striated regions indicates an agreement with the Navicula 

 lyra 1 of Ehrenberg. Its greatly elongated and hollowed valves, however, render it necessary 

 to regard it as a variety of Ehrenberg's typical species. This view has already been 

 adopted in the case of an identical form by A. Schmidt, 2 who has named it Navicula lyra, 

 Ehrenb., var. signata, A. S. The present frustule was obtained in the neighbourhood of 

 the Philippine Islands. 



1 Ehrenberg, Verb. p. 131, pL i. 1, fig. 9; Gregory, op. cit., p. 13, pi. i. fig. 13; Janisch et Kabenhorst, 

 Hondur., pi. iii. fig. 7, &c. 



2 Schmidt's Atlas, pL ii. fig. 4. i 



(bot. chall. exp. — fart iv. — 18S6.) D 5 



