MANN— DIATOMS OF THE ALBATROSS VOYAGES. 367 



makes A . thuringica Km/, a synonym of /'. angulatum I Quek. \\ . Smith, bu1 says after 

 the former, "Nomen anterius!!" Gruno the following important testimony: 



u Navicula thuringica Kg. isl aach Exemplaren von Arten im Kutzing'schen Berbar. 

 identisch mil /'/. angulatum, sodass die Art eigentlich PI. thuringicum heissen sollte." 

 Van Beurck, after quoting A. thuringica Km/., as a Bynonym of /'. angulatum and 

 following it with an exclamation point, adds this statement; "Cette espece devrail 

 done porter le uom de PI. thuringica, ce changemenl de nom esl cependanl impos- 

 sible, car cette diatomee Bi repandue et bi employee comme test, esl uni\ ersellemenl 

 connue bous le com donn6 par W. Smith." There is no question thai the chai 

 name here made is an unfortunate necessity, as this particular species is the best known 

 of all the diatoms; and it is with reluctance that the name which Bhould have been 

 accorded to it over fifty years ago is here preferred. 



Cleve adds to the above list of synonyms /'. strigosum W. Smith, * /'. normanii Ralfs,c 

 and P. finnmarchicum Cleve. d These three are alike; bul with their blunt apices, 

 smooth outline, coarser markings, and more sigmoid raphe they are very bad examples 

 of varieties of the presenl Bpecies. I><- Toni, who gives separate rank to /'. normanii, 

 unite- under /'. angulatum some impossible form-. Buch as /'. delicatulum W. Smith. < 



The variety corresponding to /'. quadratum W. Smith is very abundant al station 

 3603. 



Found at Btations 2919, 3200H, 3603, 3696, 1530H, Bonshu Maud. Japan, to Bering 

 Sea. southern California, and Santa Cruz Island, West Indies. 



PLAGIOTROPIS Pfitz. 



Plagiotropis Pfitz. in Hanst. Bot. Abhand. 2: 93. 1871. Van Hour. Synop. 121. 1881. 

 De Toni. Syll. Alg. 2: 343. 1891. Cleve & Grun. Sv. Vet. Akad. Bandl. 17-: 66. 

 1880. 



Amphiprora Ehrenb. in part; Greg. Trans. Roy. Soc. Edinb. 21: 505. pi. 12. 

 1857. 



Tropidoneis Cleve, in part; Sv. Vet. Akad. Bandl. 27 : 27. L895. 



I admit this genus with hesitation, as it is very doubtful if anything is gained by 

 separating it- form- from Amphiprora. The genus is hard to understand, on account 

 of the contorted and pellucid character of the diatoms. I lean toward a union of all 

 its forms under Amphiprora; bu1 as I have oot been able to establish a satisfactory 

 reason for this by an exhaustive study of the different Bpecies, 1 classify the single 

 species found during these investigations under it- generally accepted name, [f 

 Cleve's contention that this genus should be included in his later genus Tropidoneis 

 is correct . it would have been better to have enlarged and emended this genus ii 

 of creating a now one. 



Plagiotropis van heurckii < irun. : Van Hour. Synop. L22. pi. .' ' 1881. 



De Toni. Syll. Alg. 2: 346. L891. 

 Tropidoneis van heurckii Cleve, Sv. Vet. Akad. Bandl. 26 2 : 27. 1894. Van Hour. 



Treat. Diat. 265. pi. 6.J. :"■•. L896. 

 Found at station 2807, Galapagos Islands. 



,v 



"Sv. Vet. Akad. Bandl. 17-: 52. L880. 

 ''Ann. Ma-. Nat. Hist. II. 9: 7. pi. 1 . /. 7. L855 

 • l'ritoh. Bist. tnfus. ed. l. 919. 1861; cf. Sv. Vet. Akad. Bandl. 17-: v 

 67. L880. 

 dDenkschr. Akad. Wien 48 : L05. 1884. 

 ' \V. Smith. Synop. Brit. Diat. 1:64. pi. .; L853. 



