76 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



the circular portion of the valve included within the rim and the 

 vertical sides or flange are ornamented with massive, polished disks 

 or flattened beads, irregularly placed and variable in size, those near 

 the center usually averaging somewhat the larger ; the rim is further 

 ornamented with a row of large, elevated pearls or spherical beads f 

 best seen in the girdle view. 



Diameter, 0.096-0.124; width of vertical sides of flange, about 0.037 

 mm. Beads average 0.006 mm. in diameter. 



It is possible the Endictya form in Schmidt's Atlas, plate 62, figure 

 8 (unnamed) , from Celibes should be included here, as Schmidt states 

 its rim is ornamented with "zahlreichen knotchen tragenden Stachem." 

 There is a close but fictitious resemblance to the Philippine Islands 

 form in the Report of the Challenger Expedition (pi. 22, fig. 4) ; for, 

 if the description on page 162 is taken into account, that diatom has 

 so convex a valve that Castracane suspects it should be placed in 

 (Stephanopyxis) Pyxidicula; and furthermore, its entire valve is orna- 

 mented with "tuberculate processes having hexagonal bases." 



It is advisable that the genus Endictya shall not be combined with 

 Coscinodiscus, as is done by Rattray (Rev. Cose, p. 450), an arrange- 

 ment accepted by me in my Diatoms of the Albatross Voyages. It 

 should be retained to accommodate such forms as have valves sharply 

 bent downward at the rim to form vertical sides or flanges at right 

 angles to the surface of the circular portion. This is the position 

 taken by Van Heurck and others. It is, however, further to be said 

 that those forms which Castracane includes in his new genus Ethmo- 

 discus should perhaps also be considered to be Endictyae, their struc- 

 ture differing from such species as the below E. oceanica mainly in the 

 fineness of their markings and the general delicacy of their entire 

 frustules. This would leave for the genus Coscinodiscus that large 

 class of diatoms the valves of which, whether flat, concave, or convex, 

 terminate at the rim, where they join the girdle and are not bent 

 vertically down to form deep sides or flanges ornamented with mark- 

 ings continuous with those of the rest of the valve. In fact Endictya 

 is much more closely related to Stephanopyxis, or even to that sub_ 

 division of Melosira called Orthosira than to Coscinodiscus. 

 Type.— Cat. No 43623, U.S.N.M. 



ENDICTYA MINOR A. Schmidt 



(Schmidt, Atlas, pi. 65, figs. 14-16.) 



Although this species follows very closely the structural plan of the 

 genus type, E. oceanica, specimens of it, both fossil and recent, are so 

 uniform that it can not be classed as a small and robust variety of 

 that species. The type of the present species was found at the near-by 

 Celibes Islands. 



