330 CONTRIBUTIONS FROM PHI NATIONAL HERBARIUM. 



' taelf an arctic dredging, is another illustration of the value oi 



I i he material romp bottoms. 



• it < alifornia. 

 v - dirnpta I Edinb. 21: 191. pi. i. f. 



tbh. Schlee I erls. Cult. 1869': 3. pi B - ! (.run. in Fenzl, 



Rein So vara Bot. 1: 14. i v :<» Cleve in Nordensk. Vega Exped 

 II. I Smith, Sp. Diat. Typ. no. 633. 1874. Van Heur. Synop. pi. r>. f. \ 

 . Schmidt, Atlas pi. 196. f. 7, 1\ B8 De Toni, Syll. Al{ 1891. 



hana W. Smith, Synop. Brit. Diat. 1:22. pi B 



Jan. : Schmidt, Atlas pi. ■ 1894. 



delicatu Schmidt, Atlas pi. i ■■ . 894. 



Cleve unites under the above name, in addition to those here given, all cases of his 

 own ( . decipu ru h which are Bimilar to the above in the broadly oval character of the 

 valves, in the fineness and curvature i f the beading, in the presence of a trai 

 stauros .ii the middle of tin* lower valve, and in a general tendency toward ;> sigmoid 

 outline in the median line of one or both valves. There is much in favor of tl 

 ' pta does show these characters, even the sigmoid curvature in some insfc 



But Buch unification is here attended with confusion. The forms thus grouped are 



i Ii . C. beltmeyeri Jan., a very evident variety of C. dirupta and C.sparn- 



punctata Temp. & Brun., a very evident variety of C. decipu ns. To call these two one 

 species is carrying condensation too far for practical use. I have accordingly united 

 only the three above names with C. dirupta and have grouped all the other forms under 

 pit ns. This arrangement .though no less artificial than that of Cleve, is do more 

 bo, and ii affords an easy means of grouping these confusing forms. The salienl char- 

 acteristic of C. dirupta is, as its name indicates, a hyaline median area on ■ or both 



valves, broad at the center and tapering to a poinl at each end. Blightly or not at all 

 sigmoid. This line in C. decipiens is Blightly <»r extremely Bigmoid, the ends of the 

 raphe curved like an "S" in opposite directions, the median area generally narrow or 

 sometimes wanting, and the transverse stauros plain. It may be added that the 

 members of the C. dirupta group are generally much smaller than those belonging to 

 ( '. decipu ns. 



Pound at Btations 2690H, 1516H, off central and Lower California. 

 Cocconeis distans Greg. Quart. Journ. Micr. Sci. 3: 39. j>l. . /. 9. L855; 5: 67. pi. 1. 

 /'. ;.-,. 1857. Mfoeb. Diat.-taf. pl.5.f.9 } pi. 12./. :■'>. 1890. Schmidt. Atlas pZ. 193. 

 /. ."' ;;. \0. 1894; Jahresb. Komm. Deut. Meere2: pi. S. /. :: tS. 1874. Pritch. 

 Bist. [nfus. ed. 4.870. pi. ;./ 88. .1. L. Smith, Sp. Diat. Typ. no. 70. L874. 

 ( rrunow ' make- this a variety of ( '. scutellum Ehrenb., for which there is some war- 

 rant. As there is. however, quite a di fference between what I conceive to be t rregory's 

 type and that of Ehrenberg, I have retained the above name. The two figures of 

 Gregory's in the above citation- are not at all alike. The firsl was evidently incor- 

 Tectly drawn l>\ Tuffen West . bo far as the beading is concerned. It is represented in 

 very regular rows e\ enly graded from the Large marginal beads to the smaller medium 

 ones. But Gregory Bays,d "This beautiful form is at once characterized by the equal 

 size of the dots or granules and their great distance from each other, bo that it almost 

 Loses the aspect of Btriation." The faulty representation of this is corrected, in fact 

 over-corrected, in ( rregory's Becond figure. When the type idea of ( rregory's Bpeciesia 

 thus madeout and i- compared with Ehrenberg's original figure and description/ it 

 Beem8tomethe two are sufficiently wide apart to admit of the retention of both names. 

 Found at Btation L505H, Santa Cruz Light-house, Monterey Bay, Cal. 



Sv. Vet. Akad. Bandl. 27 : L75. L895. 

 b Bih. Sv. Vet. Akad. Bandl. r : l J. pi. t.f. 6. L873. 

 i Fenzl, Reise Novara Bot. 1: 9. L870. 

 <*Op. cit. 39. 

 ' Ehrenb. Infus. L94. pi. 14. f. 8. 18 



