326 CONTIUJJUTIONS'FROM THE NATIO^^AL IIEKBAlilUM. 



bcrs of Ehixnborg's gt'iius IIeter()mi)liala. Us type, //. huuunlidluin/f ia prol)al>ly a 

 Glypliodosniitij certainly nol, a PlagLogramnia. Do Toni,'* (jiioU's it in its t>riginal 

 geniis. Ralfw*" c-liangcvs it to rkKjiogranitnahintanttdinnt. As lie there says, the side 

 viow is unknown. How lio eoukl (hniiU* on its being a IMagii^gramma from Eln*en- 

 berg's description and williout any knowledge of its side aIow is b(^yond my eompn^- 

 hension. There are two ref(T(*nces in Elinriberg which De Toni tliinks it worth wliilo 

 to quote as members of this genus^ one^^ called with some doul)t '' IleterompJuila? 

 trinodiSj^^ a probable Navicula, and the other //. hinodis,^ whicli is either a Xavicula 

 or a Glyphudcsmis. Figure 22 of the same plate, (*alled by l']iu-cnberg simply " Anau- 

 lus — ?j'^ is, despite the central and terminal nod uh^^s^ almost certainly a i-ej^resenla- 

 tive of this g<4ius, probably V. elongatinn Grev., a fact which also indicates that 

 what he <*alls Ileteroiuphala is not identical witli llie present g(^nus. 

 Plagiogramnia elongatum Grev. Trans. Micr. Soc. Lend. n. s. 14: 121. pJ. 11. J. 1-2. 

 18Gn. Moeb. Diat.-taf. pL 74- /■ 1-2, 1890. Do Tcmi, Syll. Alg. 2: 720. l'802. 



Anavlufi sp.F Elironb. Phys. Abh. Akad. Wiss. BerL 1872: :i87. pL 2.f. 22, 1873. 

 This species is like /\ crassinn Cleve & Grove,/ except for the massive transverse 

 septa of the latter. 



Found at station 2807, Galapagos Islands/ 



Plagiogramnia sceptrum Mann, sp. nov. Plate LII, fkicres 1, 2. 



Valve elongated; sides n(^arly parallel Lo the broad rounded apices; markings of 

 small but strong beading, st^t in transverse rows, interrupted l>y a median hyaliiu' lino, 

 two beads wide, running m^arly the entire length of the valve, that is, from one ajiical 

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

 apical areasj in this genus usually hyaline or faintly mottled, Iutc beaded with sligluly 

 smalhu- beads, spread out fan-wise toward the sides and apices of tlu^ A^alvc and traversed 

 by a thin irn-gular median line continuous with the median line of the rest of the valve; 

 bonhT not plain, hut ornnmunt(^d with a single row of beads larger than the rest. 

 Instead of transverse ^'vittae'' there art' strong internal transverse septa, not contin- 

 uous acrt>ss the valve, but usually sti.>pping at the position of the hyaline^ median line 

 before mentioned and generally not oi>posite each other on the two sides of tln^ valve; 

 central area quite small, not reaching the bordir, transversely oval and b(*aring a 

 decided boss in the middle; zonal vi(^w showing tlu^ internal septa enlarg(^d at the 

 inner ends like tlu* music-notes of Trrpnnoc ivusica Ehr(^id>.; the septa as seen 1)oth 

 in zonal nnd vah^al vicnv, placed at very irrc^guku- distanc<"s, th(Te being from two to 

 seven rows of beads b(^twe(Mi them; girdle with two faint longitudinal ridges di\ iding 

 it into thirds, biit no beading. 



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



The only species at all like this one is I\ rcctnnt Cleve & Grove. The resemblance 

 is merely superficiaL 



Type in the U. S. National Mtisenm, No. 590141, from statit)n 2807, Galapagos Is1au<ls, 

 April 4, ISSS; 812 fathoms, bottom of Ghjbigerina ooze and coral mud. 



Plagiogramma tesselatum Grev. Quart, .bjuru. Miu\ Sci. 7: 208. pL 10. f. 7. 1859. 

 Moeh. Diat.-taf. pi 24- f- 7, 1890. Pritch. Hi^t, Infus. ed. 4. 774. ISGl. Lewis, 

 Proc. Acad. Phila. 1861: ()8. 1802. Dc Toni, Sylb Alg. 2: 719. 1892. Grun. 

 Verb. Zool. Bot. Ges. Wien 12: 359. 1802. 



The absence of internal transv<^rse septa in lliis species led Greville to havesome 

 doubt of its right here. Grunow thought it nught be made a new gtnius. Ex( ept for 



(^Ber. Akad. AViss. Berl. 1858: bb 1859. 



^'DeToni, Syll. Alg. 2: 7:50. IS92. 



<^ Pritch. Hist. Tnfus. ed. 4. 775. 1801. 



dBer. Akad, Wiss. Berl. 1861: 295. 1802, 



^Phys. Abh. Akad. Wiss. Berl. 1872: />/. 2. G. 23. 1873 



fLe Diatomiste 1; 54. pi S.J. 4-5. 1891. 



