MB. W. JOSHUA ON BUBMESE DESMIDIRS. 643 



S. gbanulatum, Reinsch. (Plate XXIV. figs. 4 & 5.) 



S. OEBICULABE, Halfs. 

 S. POLYMOEPHUM, Bret. 



S. fubcatum, Ehrb., Breb., /3. senabium, Ehrenb., Nordst. 

 (Plate XXIV. figs. 6 & 7.) 



S. leptacantha, f . 9-gona, Nordst. 

 S. leptodekmum, Lundell. 



S. MINUSCULUM. 



S. platycebum, n. sp. (Plate XXIV. figs. 1 & 2.) 

 S. cytiodermate lsevi, [pellucido : cellulis a fronte conspectis 

 ovatis, brachiis triplo longioribus quam latit. corporis ipsius ; 

 apicibus divergentibus, tricuspidatis, marginibus hirsutis, proini- 

 nentiis spinosis regulariter dispositis ; radiis 4, 5, raro 6. Cel- 

 lulae latit. ad basin 18 /u, brachii longit. cum spinis 33-50 ft : ex- 

 pansio brachiorum ■ 83-160 /x. 



Cytioderm smooth and transparent ; cells in front view ovate ; 

 arms 3 times as long as breadth of body ; diverging apices tricus- 

 pidate; margins rough with regularly placed spinous protu- 

 berances ; rays four, five, rarely six. It comes nearest S. aspi- 

 nosum, Wolle, but has not the slender rectangular spines, and 

 is a larger species. Width of cell at base 18 /x ; length of arm, 

 including spines, 33 ix, 50 /x ; spread of arms 83 /x, 160 /u. 



9. Xanthidium, Ehrenb. 

 X. armatttm, Breb. 



X. ACANTHOPHOBUM, Nordst. 



X. ANTILOPEUM, KutZ. 



X. ANTILOPEUM, f. JAVANICA, Nordst. 



X. ANTILOPEUM, /3. TBIQUETBUM, Lund, f. BBASILIENSE, Nordst. 



X. antilopetjm, f. angulatum, n. var. (Plate XXIV. fig. 16.) 

 X. a fronte conspectum quadrangulare, minute punctatum, 

 apicibus convexis ; cellulis plus duplo latis quam longis, profunde 

 constrictis, angulo lineari, nee infiatis nee granulatis ; apicibus ? 

 angularibus, apud punctos singulos spinam longam subulatam 

 ferentibus. Latit. sine spinis 48 xx, cum spinis 98 xx: isthmi 

 latit. 10 fi. 



In front view quadrangular, with convex ends, minutely punc- 

 tate ; cells rather more than twice as wide as long, with deep con- 

 striction, angle linear ; no inflation or granulation ; apices angular, 



