326 INTRIBUTI0N8 PROM Mil. NATIONAL HERBARIUM. 



I Ehrenberg's genus Beteromphala h- type, U. himantvHum* is probably a 

 Glyphodesmis, certainly nol a Plagiogramma I >«• Toni,* quotes it in itc original 

 Ralfs< changes il i" Plagiogramma himantidium. As be there says, the side 

 vie* i- unknown. Ho* be could decide on its being a Plagiogramma from Ehren- 

 •i|»ii-.n and without any knowledge of its side vie* is beyond my compre- 

 hension. There are two references in Bhrenberg which De Toni thinks il worth while 

 i" quote ae members of this genus, one*' called with some doubt u HeUromphaia t 

 i probable Navicula, and the other //. binodis,* which is either a Navicula 

 or a Glyphodesmis. Figure 22 of the same plate, called by Bhrenberg simply "Anau- 

 lus ?," is, despite the central and terminal nodules, almost certainly a representa- 

 tive of this genus, probably P. elongatum Grev., a feet which also indicates that 

 what be calls Heteromphala is not identical with ih<' present genus. 

 Plagiogramma elongatum Grev. Trans Micr 8oc. Lond.n. s.14: [2l.pl. 11. f.l l. 

 L866. Moeb. Diat.-taf. pi. 74. / t 1890. De Toni, Syll. Alg. 8:720 



Arutulua >!»..• Ehrenb. PhyB. Abh. Akad. WisB. Berl. 1872::'^: pi. I. J 



This species is like P. crawum Cleve & Grove,/ except for the massive tram 

 septa of the Latter. 



Pound at station 2807, Galapagos [slands. 

 Plagiogramma sceptrum M;i ii ii. >|>. nov. Pi \n I.I I. ik.i i:i> 1. 2. 



Valve elongated; Bides oearly parallel to the broad rounded apices; markinj 

 small bul Btrong beading, eel in trans\ erse rows, interrupted by ;i median hyaline line, 

 two beads wide, running nearly the entire Length of the valve, that is, from one apical 

 area to the other; four to five beads in each half row on either side of the median line; 

 apical areas, in this genus usually hyaline or faintly mottled, here beaded with slightly 

 Bmaller beads, spread oul bin-wise toward the sides and apices of the valve and tra\ ersed 

 by a thin irregular median Line continuous with the median Line of the rest of the valve; 

 border nol plain; bul ornamented with a Bingle row of beads Larger than the rest. 

 Instead of transverse "vittae" there are Btrong internal transverse Bepta, not contin- 

 uous across the valve, but usually stopping at the position of the hyaline median line 

 before mentioned and generally not opposite each other on the two sides of the valve: 

 central area quite small, nol reaching the border, transversely oval and bearing a 

 decided boss in the middle; zonal view Bhowing the internal Bepta enlarged at the 

 inner ends like the music-notes of Terpsinoi musica Ehrenb.; the septa as Been both 

 in zonal and valval view, placed at very irregular distances, there being iv<>\\\ two t<> 

 seven rowB of beads between them; girdle with two faint longitudinal ridges dividing 

 it into thirds, bul no beading. 



Length of valve, 0.200 to 0.212mm.; width of valve, 0.027 to 0.029mm. 



The only species at all like this one is /'. rectum Cleve & Grove. The resemblance 

 is merely superficial. 



Type in the CJ. S. National Museum, No. 5901 11. Eromstation 2807, Galapagos Islands, 



April 1. l ss v B12 fathoms, bottom of Globigerina ooze and coral mud. 



Plagiogramma tesselatum Grev. Quart. Journ. Mi< r. Sci. 7: 208. pi. 10. f. 7. 1859. 



Moeb. Diat.-taf . pi :,./. 7. L890. Pritch. Bist. [nfus. ed. 1.774. 1861. Lewis, 



Proc. Acad. Phila. 1861: 68. L862. De Toni, Syll. Alg. 2: Tin. 1892. Grun. 



Verb.. Zool. Bot. Gee. Wien 12: 359. L862. 



'Ihc absence of internal transverse Bepta in this Bpecies led Greville i<» have some 

 doubt ofitsrighl here. Grunow thought it might be mad.' a new genus. Except for 



Ber. Akad. Wiss. Berl. 1858: L3. L859. 

 b De Toni, Syll. Alg. 2: 730. L892. 



Pritch. Bist. [nfus. ed. 1. 775. L861. 

 d Ber. Akad. Wiss. Berl. 1861: 295. L862, 

 ' Phys. Abh. Akad. Wiss. Berl. 1872: pi. I 

 J I.e Diatomiste 1: 54. pi. 8. i ■ 5. L891. 



