m^'"rf 



MAXX DIATOMS OF THE ALBATROSS VC^'AGES- 327 



thi.- lark it i.s a prrfcH'tly typical riagiograinnuij and this iK^gativc ([ualily is iiisufii- 

 cioTit for separating iL Specimens found in the following <ln'<lging have a circular 

 ccniral area and nearly round instead of nniangular or '^tcsst^lat^Hr' l>eading. 

 Found at station 2808, Calapagos Islands. 



DIMEREGRAMMA Ralfs. 



Dinicregramma Ralfri in Priuh. llist. Infus. ed. 4. 790. pL .;./. .13-35. 1801. Raldi, 

 Kh Hur. Alg. 1: l:?. 12:h/. 36. 18G4. Van II. -ur. Synop. 140. pj. 3fLf .7 /.;. 1881- 

 1885. De Toni, Syll. Alg. 2: 711. 1892. Walk. & Cliase, Xotes on Diat. 1: 1. 

 pi. /./. .L188G. Grun. Vcrh. Zool. Bot. Ges.'Wien 12: 1177. 18G2. Pritcli. U\^L 

 Infus. ed. 4. 790. pi. -j.f. 34. 18G1. 



Denlicula Kiilz. in part; Greg. Trans. Roy. Soc. Edinlj. 21: -195. pL 10. f. 39. 1857. 



The nearest genus t(jthi.^ isGlyphodesmis Grev.. from which it differs by the absence 

 of a large central boss. This single characLeriritic is, however, sLriking a]id uniform, 

 CasLracane'f is wrong in staling that the only distincti(^n between this gemis and 

 Denticula Xiitz. is that (In* former lias snuMtlh sides to the valves. Dini<T(^gramma 

 may have the same; but it has a pronounc^ed hyaline mc<lian line, ''pseudoraphe/' 

 dilated at the center^ is without transverse costae, and has large bossdike elevations 

 at the apices (seen clearly in the zonal view), all which distinct i(Hi.s are inapi>licab]o 

 to Denticula. 

 Diniere gramma infiatum. Mann^ sp. nov, Plate XLIV, j-KiCRK G. 



Valve seven to eight times as long as broad^ inflated at the center, with bluntly 



\ taporing ends; at the apex of each a large beakdike protu'ss; valves marked with 



transverse rows of beading, extending from the margin for one-third the width of iho 



valve, leaving a median hyaline area, also on(^-lhii'd thi' width (»f the valve; each row 



consisting of four beatls, the outer largest and decreasing in size toward the center. 



Length of valve 0,08(1 mm; width of valve 0.015 mm. 



Type in the U. S. National Museum, No. 590142, from station 2823, Gulf of (Vdifor- 

 nia, April 30, 1888; 2G.5 fathoms, bottom <jf broken shells. 



The nearest form to this is D. marininn (Greg.) Ralfs, ^ but I have found it impossible 

 Lu refer it Lo that species. Gregory's foiin has striae with two beads somewhat s(^pa- 

 rated, Iheir line being ^Mmtinued outward l<» tlic margin by bars or costae; wliereas 



the nioniliform lines in my species begin wilh very larg<^ marginal beads and end 

 inward with beads of extreme minuteness. Indeed the whole l)uild of the diatom is ' 

 disiinc^t. 



ACHNANTHES Bory, 



Aclmanthes liory, Die. Hist. Nat, 1: 79. pL 51, f. 2, 1822. 



Monogramma Ehrenb. IJer, Akad. ^\'iss. Rerl. 1843: ]'M\. 1844, no species, 1854, 



not Comm. 1809. 

 Achnanthidium Kiitz. Jhu'ill. 75. 1844. 



Achnanthes dispar Mann. sp. nov. Platk XLIV, fioures 4, 5> 



Under valve beaded with minute nioniliform striae, transverse until near the ends, 

 then bec<nning concentric to the points of the apices; the raphe inade up of a closely 

 s<'t but nioniliform line (jf exceedingly small beads, at least toward its cenlral and 

 terminal portions, an<l forking near each end into two branches, one proceeding to llio 

 rounded apex and terminating in a smull bead, the other and slu^rter Ijranch nnniing 

 to one side and also t<Tminating in a sjnall b*'ad; a narrow liyaline area on either si<le 

 of tile raphe; the transverse, median, hyaline stauros broad and increasing at the 



'r Castr. Rep. Voy. Ghall. Bot. 2: 4G. 188(J. 



^ Trans. Roy. Soc. Edinb. 21: 49G. pi. 10. f. 39. 1857, Pi itch. Hist. Infus. ed. 4. 

 90 18G1. Van Ileur. Synop. pL SG.f. 9. 1881. De Toni, Syll. Alg. 2: 712. 1892. 



;nTi.^— VOL 10, FT r.— 07 — -8 



