Species of Diatoms from Hongkong. 5 



ated so as to appear annulate ; connecting processes very nu- 

 merous, very short, linear, obtuse. 

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

 Palmer, Esq. 



A fragile little species, seldom found quite entire, and gene- 

 rally in solitary frustules; but I have repeatedly seen two in 

 connexion, and have at the present moment a chain of three 

 under my eye. I liave not been able to perceive any cellulation ; 

 but the annulate character is very obvious. The length of the 

 frustule is about '0010"; the breadth a little less. 



I take the present opportunity of mentioning that in speci- 

 mens burnt on the cover, and mounted dry, I have observed 

 indications of an annulate structure in C. cylindracea, to which 

 our new species appears to be allied. 



Genus Hemiaulus. 

 Hemiaulus chinensis, n. sp., Grev. PI. V. fig. 9. 

 Frustules rectangular, very minutely punctate ; the angles pro- 

 duced into linear-attenuated horns, tipped with a spine ; space 

 between the horns nearly straight. 

 Hab. Hongkong Harbour ; J. L. Palmer, Esq. 



Like Hemiaulus Polycystinorum and others of the genus, the 

 present Diatom is most inconstant in point of size, not so much 

 in the length as in the breadth of the frustules. I have them 

 from "0007" to '0030". It is a delicate and transparent species, 

 and liable to be overlooked, unless burnt on the cover previous 

 to mounting. At the sutural line the puncta are exceedingly 

 minute, and gradually increase in size to the surface of the valve 

 included between the horns. I am not acquainted with any true 

 species of Hemiaulus in which the punctation is so minute. The 

 horns are somewhat truncate, and furnished with a terminal, 

 slender, short spine. 



In his memorandum sketch, Mr. Palmer has represented the 

 valve, a view of which I have not been so fortunate as to obtain. 



Genus Amphiprora. 

 Amphiprora lepida, n. sp., Grev. PI. V. fig. 10. 

 Front view broadly linear, elongated, rounded at the ends, very 

 slightly constricted in the middle, and with a marginal row 

 of very minute puncta ; middle portion grooved with straight 

 longitudinal lines. 

 Hah. Hongkong Harbour ; in material transmitted by Mr. J. L. 

 Palmer. 



Well characterized by its narrow form, almost straight mar- 



