32 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



one-fifth of the margin, where they slightly expand around eight 

 strong, round, slightly protuberant processes; the rows of large, 

 widely spaced beads bordering the eight radii are perfectly straight, 

 the other rows in each of the eight sectors being parallel to the med- 

 ian row ; no crowding of beads toward the margin. 



Diameter, 0.070 mm. 



The large, widely spaced beading of this species, its flat surface 

 surrounded by a rapidly depressed outer band, and the strongly 

 recessed circle of processes give to it a unique appearance. 



It resembles somewhat A. amoenus Greville (Schmidt, Atlas, pi. 34, 

 fig. 6) and more closely the unnamed figure in Schmidt's Atlas, plate 

 133, figure 7. 



Type.— Cat. No. 43584, U.S.N.M. 



Genus AULISCUS Ehrenberg 



AULISCUS CAELATUS Bailey 



(Smith. Contrib., 1854, p. 6, figs. 3-4; Schmidt, Atlas, pi. 32, figs. 14-15) 

 The type form and a large number of varieties were found includ- 

 ing var. delicatula Rattray (Rev. Auliscus, p. 886, pi. 15, fig. 5) and 

 var. latecostata A. Schmidt, (Atlas, pi. 32, figs. 16-20) the latter be- 

 ing a Campeche Bay form. 



AULISCUS COMPOSITUS A. Schmidt 



(Schmidt, Atlas, pi. 30, fig. 9.) 



AULISCUS PHILIPPINARUM, new species 



Plate 6, fig. 4 



Valve slightly oval, long axis passing slightly to the left and right 

 of the two processes; central hyaline area large, somewhat rectangular; 

 two processes (ocelli) of moderate size, strongly ringed, tilted obliquely 

 outward, set close to the margin on two wedge-shaped elevations, 

 which are coarsely rugose with irregular-shaped beads; the rest of the 

 valve ornamented loosely with curved strings of heavy beading radi- 

 ating from two club-shaped areas which extend from the central area 

 right and left to within a short distance of the margin; valve and all 

 markings massive and glistening. 



Long diameter, 0.082-0.159. 



This spectacular diatom is abundant in the Philippines. It is very 

 nearly the same as one figured in Le Diatomiste (p. 2, pi. 2, figs. 4-5) 

 but misnamed A. oamaruensis, var. madagascarensis Tempere and 

 Brun. It has some resemblance to A. hardmanianus Greville, includ- 

 ing the fossil form from Monterey, Calif., and especially as it is figured 

 in Schmidt's Atlas, plate 89, figure 4, from a Santa Monica, Calif., 

 specimen, also fossil. But to unite this clearly distinct and constant 

 form with either of the above fossil species would be unwise. 



Type.— Cut. No. 43585, U.S.N.M. 



