KEPOKT ON THE DIATOMACEiE. , 155 



from the Coscinodiscus concinnus of W. Smith, with which it agrees in its other charac- 

 teristics. Although such a difference is a small one, its specific value must still be 

 admitted. Coscinodiscus papuanus was collected in the neighbourhood of New Guinea. 



Coscinodiscus denticulatus, n. sp. (Plate III. iig. 8.) 



E maximis ; striis aequalibus, radiantibus ; superficie denticulis sparsim uotata ; mar- 

 gine striato distincto. Diametrum=130 fx. In mari Pacifico. 



This large Diatom is covered with uniformly radiating granules, while the surface of 

 the valve also bears at intervals more prominent denticules. The margin is formed by a 

 distinct band, which is delicately fluted and separated from the valve by a well-defined 

 line. The specific name which has been applied has reference to the prominent valval 

 denticules. 



Coscinodiscus^stellaris, Roper, var. nov. (Plate III. fig. 2.) 



The frustule here delineated was found near the ice-barrier of the Antarctic. It consists 

 of a very small disc which is ornamented by lines of minute radiating puncta of so great 

 delicacy that it has been found impossible to represent them adequately in the figure. 

 The centre is marked by a cross formed of four oblong granules analogous to those found 

 in Coscinodiscus stellaris, Eoper, 1 of which the present form must be regarded as a variety. 



Coscinodiscus centralis, Ehrenb., var. nov. (Plate II. fig. 3.) 



A variety of Coscinodiscus centralis, Ehrenb., 2 is here shown. It was collected in the 

 Sea of Japan, and only differs from the typical specimen in possessing a fluted margin 

 which is entirely absent in the latter. 



Coscinodiscus variolatus, n. sp. (Plate II. fig. 5.) 



Granulis parvulis aequabbus, fasciculatim radiantibus ; superficies granulis elevatioribus 

 maculata. Ad insulas Philippinas. 



The present small but very elegant disc from the neighbourhood of the Philippine 

 Islands is ornamented with small but distinct granules, which are disposed in fascicules 

 consisting of parallel lines. The surface is spotted and the spots result from small groups 

 of granules which rise beside one another in the form of denticules. The specific name 

 has reference to the pitted appearance shown by the surface of the valve. 



Coscinodiscus patera, n. sp. (Plate II. fig. 6.) 



Forma umbonata; area umbilicali nonnullis punctulis notata, a qua punctulorum linear 

 radiantur, quandoque prope marginem cessantes. In mari Pacifico. 



1 Micr. Journ., vol. vi. p. 21, pi. iii. fig. 3 ; Pritchard, pp. cit., p. 828, pi. v. fig. 83. 



2 Ehrenberg, Mikrogeologie, pL xviii. fig. 39 ; Gregory, Diatoms of the Clyde, p. 28, pi. iiL fig. 49. 



