REPOKT ON THE DIATOMACE^E. 105 



named Biddulphia weissflogii by Grunow, who gives South Africa as its locality. The 

 Challenger Diatom must accordingly be designated by the same specific name. 



Biddulphia (Amphitetras) ornata, Shadb., var. hirsuta, nov. (Plate XXIII. fig. 9.) 



The frustule here shown recalls the Amphitetras ornata of Shadbolt, 1 as it agrees with 

 the latter in its quadrate form, its concave sides, the evident granulation, and the reticu- 

 late linear veining. On comparing the present form, however, with the specimen of 

 Amphitetras ornata of the Typenplatten of Moller, it may be observed to differ in the 

 somewhat greater concavity of the walls and the consequent prolongation of the extremi- 

 ties, and also in the presence of a corona of spines or puncta. Moreover, the precision 

 with which the details of sculpture are represented in the Typenplatten show that the 

 valve is not flat, a feature which could not be seen in the present case. Notwithstanding 

 these differences, the Challenger frustule, which was collected in the Sea of Japan, can 

 only be viewed as a variety of Shadboldt's species, which, however, should receive the 

 generic designation Biddulphia, instead of Amphitetras. 



Biddulphia (?) sp. (?) (Plate XIX. fig. 1 ; Plate XXX. fig. 9.) 



A very singular Diatomaceous frustule is shown on Plate XIX. fig. 1, and again under 

 a somewhat higher magnifying power on Plate XXX. fig. 9. The two figures have been 

 given because of the omission of a character of great importance in the former, namely, 

 the occurrence of a small area, ornamented with small crowded granules, at each of the 

 rounded angles of the slightly concave side, a peculiarity which occurs in Triceratium, 

 arcticum, Bright. As only one specimen of this form has been observed, it has been 

 found impossible accurately to determine to which genus it belongs. The slight pro- 

 minence of the two adjacent extremities of the concave side seems to point to its being a 

 Biddulphia, but the marked want of symmetry in the two valves opposes this view, 

 although this last circumstance may point to the fact that it may have formed part of a 

 seriate Diatom, of which it may have represented the terminal frustule, thus recalling the 

 irregular appearances that are found in many forms of Chastoceros and Bacteriastrum. 

 The characters of the frustule are the following : — Zonal profile of frustule subquadrate, 

 with one side slightly concave ; angles rounded ; two transverse diaphragms or septa 

 dividing the frustule into three approximately equal parts ; surface of parietes covered 

 with thinly disposed subparallel rows of oval granules ; granulation becoming abruptly 

 crowded and more delicate near the angles on the concave side. Locality : Sea of 

 Japan. 



The frustule was found in a preparation generously placed at my disposal by Dr James 



Rae, R.N. 



1 Trans. Micr. Soc. Lond., vol. ii. p. 16, pi. i. fig. 10. 

 (bot. chall. kxp. — part iv. — 1886.) D 14 



