14 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



with A harbadensis Greville in Schmidt, Atlas, plate 132, figure 1, 

 and A. grayii Grove in Schmidt, Atlas, plate 184, figure 1. Some of 

 my specimens have 9, others 14 divisions. Janisch (Gaz. Exp., pi. 

 20, figs. 18-19) accurately figures it but calls it Polymyxus schleinitzii. 

 Polymyxus Bailey, based upon P. coronalis, can not be successfully 

 separated from Aulacodiscus; but Janisch's specific name, schleinitzii, 

 given in 1888 (1889?) antedates that of Schmidt, 1890. However, 

 this can not go over with Polymyxus into Aulacodiscus, seeing that 

 it has a decided ridge traversing each elevated sector of the circle and 

 ending at the margin in a sessile ocellus, not in a pedicelled horn. 



Genus ACTINOPTYCHUS Ehrenberg 



ACTINOPTYCHUS ANNULATUS (Wallich) Grunow 



(Van Heurck, Treat., p. 495, fig. 237; Micros. Journ., 1856, pi. 12, fig. 15.) 

 There is reason for looking on this generic classification with 

 dissatisfaction, and several other assignments of this diatom have 

 been made. Wallich's original name was Triceratium annulatum. 

 Grunow (Bot. Centralblatt, vol. 15, No. 10, p. 36.), suggested the 

 new generic name, Cymatogonia. De Toni (Syl. Alg., p. 1395) proposed 

 the untenable new genus Schuettia and unites this form with the sim- 

 ilar Actinoptychus amblyceros (Ehrenberg) A. Schmidt, the less similar 

 Triceratium marylandicum, Brightwell and T. neogradense Pantocsek, 

 and the wholly unlike T. trigonium A. Schmidt and Actinoptychus 

 trilingulatus (Brightwell) Ralfs. On the whole the position taken by 

 Van Heurck, who retains this form in Actinoptychus, is the least 

 unsatisfactory one. (See Van Heurck, Treatise, p. 496.) 



ACTINOPTYCHUS AREOLATUS (Ehrenberg) A. Schmidt 



(Schmidt, Atlas, pi. 1, fig. 9.) 



It is doubtful if this can be held as a valid species rather than a 

 wide variety of the variable A. undulatus (Bailey?) Ralfs. But it is 

 the prevailing f orm in the Philippine Islands, where it contrasts rather 

 sharply with the typical A. undulatus. 



ACTINOPTYCHUS HEXAGONUS Grunow 



(Schmidt, Atlas, pi. 1, figs. 15-17.) 



Large and elegant specimens of the truly hexagonal form are not 

 uncommon in the Philippine Islands, as well as a great variety of 

 gradations into strictly circular specimens. 



ACTINOPTYCHUS HISPIDUS Grunow 



(Van Heurck, Synopsis, pi. 123, fig. 2.) 



ACTINOPTYCHUS JANISCHII Grunow 



(Schmidt, Atlas, pi. 153, figs. 8-10.) 



