6 Dr. R. K. Greville on new Genera and 



gins, and ribbed appearance of the connecting zone. I cannot 

 perceive any trace of striae or of supplementary wings. The 

 length of the frustule is -0065" ; breadth in the middle -OOIO". 



Amphiprora hyalina, n. sp., Grev. PI. V. fig. 11. 



Hyaline j front view divided, by a deep and sharp constriction, 

 into two roundish lobes, with a row of extremely minute 

 marginal puncta, and a second inner row of irregular ones ; 

 supplementary wings forming a single curve; connecting 

 zone with longitudinal lines. 



Hah. Hongkong Harbour; in material communicated by J. L. 

 Palmer, Esq. 



I oflfer this species with some little apprehension that it may 

 turn out to be an extraordinary variety or condition of A. alata. 

 Assuredly it appears to have absolutely nothing in common with 

 the figures given by Prof. Smith in his ' Synopsis of the British 

 Diatomaceae •' but it more nearly resembles Kiitzing's figures in 

 his ' Bacillarien/ which, although not quoted in Pritchard's 

 ' Infusoria,^ are copied in the plates. These figures, however, 

 are somewhat confused, and, being deficient in details, cannot 

 be regarded as definitive. There is, if I may be allowed the 

 expression, a great difference in the physiognomy of the Chinese 

 Diatom. The supplementary wings also, which sweep down and 

 intersect the lines of constriction, constitute an important cha- 

 racter. I have been unable to observe whether the wing be 

 continued round the ends, as is said to be the case in A. alata. 

 The marginal puncta are much more minute than in that spe- 

 cies ; and I cannot make out any striae. Length -0028", breadth 

 •0018". 



Amphiprora venusta, n. sp., Grev. PI. V. fig. 12. 



Front view broadly panduriform, truncate at the ends ; wings 

 widely rounded at the corners, and then rapidly constricted ; 

 supplementary wings narrow, passing in a single curve within 

 the nodule, striated ; margin strong, with a row of minute 

 puncta. 



Hab. Hongkong Harbour; in material communicated by J. L. 

 Palmer, Esq. 



This species possesses a considerable likeness to A. alata 

 (Edin. New. Phil. Journ. vol. xviii. pi. 1. fig. 13), but differs in 

 its strong margin, in the row of marginal puncta, and in the 

 apparent absence of striae in the wings. In general outline it is 

 also very similar to A.Meneghiniana and A. Brebissoniana [loc. cit. 

 pi. 4. figs. 7, 8) ; but here the single curve of the supplementary 

 wings, besides other characters, removes it at once. In the dry 



