252 COKTRIBUTTONS l^HOM THE NATIONAL HERBATUTTM. 



Coscbwdiscus labyrinthns Ropor, Quart. Journ. IsVicr. Sci. 6: 21. pi S.f. 2a-h. 1858. 

 Moeb. DiaL.-Uif. j>?. 29, /. 2 a-b. 1890. rrilch. Hist. Infus. od. A. 8:^1. Halt. 

 ■ Proc. Roy. Soc. Eclinb. 16: 171. 188U. Cleve & Moll. typ(> no. 27(i. De Toni, 

 Syll. Alg- 2: 1215. 1894. Gmu. Dt^'ukschr. Akad. Wienf^ 48-: 73. 1884. 



As the central portion of C. sol Wallich and this spc^cies are almost idontical, and 

 as the outer border is weakly HilieifiiKl and easily destroyed, specimens of the two 

 may easily be confuised. It may uUiniately be found that the two are only striking 

 varitrties of the same species, in which ease O'Meara's E. exceniricus would represent 

 an intermediate form. Comparing it wilh the second figure of C sol^ whei'e the invest- 

 ing ring is greatly reduced, it is (^asy to see how an extension of the ]>uncta into 

 lin(^s in the otherwise hyaline border of CAfeara^s form, and a reduction in llie deposit 

 of silica would give us C soL Variati<m in these respects is by no means unl^IH»wn. 

 An analogous ease will be found described under C. robustiis Grev., where in some 

 cases a massive investing ring is present, no trace of Mhich is to fotmd in most examples 

 of that species- There is, however, at this time no justification for rlaiming 1li(^ 

 identity of C\ exceniricus and C, soL 



Tlie variety called C. labyrinlhu^ by Uoper occurs at station 4505II. The pc^cuUar 

 symmetrical grouping of the hexagons that gives a strongly dotted appearance to the 

 valve is obscure wh(^n mounted in Canada balsam, but very striking in the dry speci- 

 mens. Finding this in connection with large quantities of C. exceniricus, I have 

 bec^n able to estal)lish beyond questimi that this is simply a variety of tlu' above. It 

 is given separate rank by Ralfs, Schmidt, Rattray, and De Toni. It should be h(Te 

 stated that Schmidt's plate 59, figiu'e 14, has notliing to do with the above forms. 



Found at stations 2807, 2844, 2859, 3091, 33(J1H, 2C04II, 3G9:31I, 3(J94JI, 209911, 

 4023II, 4025II, 450611, Galapagos Islands, off Kamchatka, south of Alaska, (jff Oregon, 

 Berijig Sea, off California, and Okhotsk Sea. 



Coscinodiscus galapagensis Ratt. Proc. Roy. Soc, Edinlt. 16: 574. pZ. 2.f. JO. 1889. 



De Toni, Syll, Alg. 2: 1285. 1894. 



/ 



/. 1. 1881. 

 Coscinodiscus griscus Grev.; Schmidt, Atlas pL 5S,f. 1. 1878< 

 Coscinod.scus scinlillans Grev.; Schmidt, Jahresb. Komm. Deut. Meere 2: pL fl, 



/. S3. 1874 (?). 

 Coscinodiscus appolinis covipada Ratt. Proc. Roy, Soc. Edinb. 16: 579. 1SS9, 



I think Rattray is correct in making tliis a new species rather than a variety of 

 C. grUcus Grev. Greville's species '> is (piite diff(a-ent. I also think the f(jrni cited 

 above as C scinlillans Grev. (?), which Rattray makers subspecies compacta of (A 

 appolinis Ehreid)., is the same diatom. Indeed, the only doubt of the validity of 

 Rattray's species is Its closeness to forms uf C. scinlillans Grev. (C. appolinis I'^hrenb.), 

 as represented in this figure of SchmidtVs, rather than to forms of C. griscus. 



Found at station 2808, Galapagos Ishmds. 



Coscinodiscus heteroporus Ehrenb. Rer. Akad.Wiss. Berl. 1844: 205. 1845. Priteli. 

 Hist. Infus. ed. 4. 83E 1801. Grun. Denkschr, Akad. Wien 48-: 74. 1884. 

 Schmidt, Atlas pL 61. f, 7, 4, (7?). 1878. Rati. Proc. Roy. Soc. Ediid>. 16: 

 540. 1889. De Toni, Syll. Alg. 2: 1202. 1894. 



Rattray refers Schmidt's figure <" to ( '. decrescens Grun. As stated un(K'r that species, 

 I think Schmidt is correct in assigning it here. Figure 7 is dou1>tful. 



1. 



Found at station 3509II, Pribilof and ^Commander Islands. 



aCf. Trans. Micr. Soc. Lond. n. ^. 8: 38. pi ;?./. 1-2. 1800. 



^Qiiart. Journ. Mier. Sci. n. s. 3: 230. pi 9./. 7. 1803. Moeb. Diat.-taf. pL47j-7 



1890. 



<• Schmidt, Atlas pi 01./. 6. 



