MANN DIATOMS OF THE ALBATEOSS VOYAGES, 



353 



i 



Diatoniaceen, ^^ plate 1, figure 39, and Schnn^lt's Atlas, plate 2, figure 29. IL dho \i\xs 

 conpidorable resemblanre to Schmidt's Allap, jjlate 2, figure 10, N. hiitoniana Selnnidt, 

 which Clevc^^ makes a vari(^ty of N. approrimata Grev.; tliough how he ran s(^e N, 

 approxhuata in that furui and N. lyra in th(^ form figured l)y Janisch just mentionoil is 

 beyond my understanding. "Whether or nut tlie form r(^preKenled by Janiech's figure, 

 the A^. hiitoniana of Se]nni<h, and my .specimen should be chistied as a variety of N. lyra 

 is a qvietition of the limils of a species and the degree of dissimilai-ity it is desirabh^ to 

 include imder one name. Taking the view that it is advanlag(H)us to add as few nt^w 

 forms as possible to the alrc^ady enormous species N, hjra^ I have given the above 

 name. For reasons mentioned in llie intnKbiction, the naming of varieties is not 

 favored by the writt^r. It may be ntjted that my specimen differs in several respects 

 from the two I have here a^ssociated with it, especially in the H-shapod hyaline spat^ 

 n(»t having its tips approacli, but strictly parallel, whereby the central rows of striae 

 are of the same width from tln^ apices to the (enter. But the minor <lifferences between 

 my form and that of Janisch's above can n(»t make them two species. 



Type in the U. S. National Museum, No. 590149, from stati(m 292011, Hawaiian 

 Islands, November 21, 1891; 570 fathoms, bottom of brown mud and fine sand. 



Navicula sandriana Orun. Verb. Zool. Bot, Ges. Wien 13: 153. pi. IS. f. 5. 18G3, 

 Schmidt, Atlas p?. S.f, 10, 1875; pL 70. f. io. 1881. O'Meara, Troc. Roy. Irish 

 Acad, II. 2: 388. pi. 32. f. 29. 1875 (figure poor). Lagers. Bih. Sv. Vet. Akad. 

 Handh 3^^: 41. 1S7(;. De Toni, Sylb Alg. 2: 105. 1891. (4eve, Sv. Vet. Akad. 

 Ilandl, 27^: 59. 1895. 

 Navicula rimosa Grt^v. Trans. Micr. Soc. Lond. n. s. 14: 129. pi. 12. /. 25. 18Gfi* 

 Moeb. Diat.-taf- pi. 75. f. 25. 1890. 



It seems to me the original fignres of l)oth the above give emphasis to a rather incon- 

 stant feature of this diat<jm, namely, thenarrow sickle-shaped line of striae midway 

 between the center and the margin. This is very lialjle to be reduced to a somewhat 

 indefinite granulation blending with the more indistinct granulation about it. In 

 fact, there are unmistakable varieties iu which these sickle-shaped lines can virtually 

 disappear. In such a case we are confron((*d l^y the question in what respect such a 

 form is separable from varieties of iV. hennedyi and N. praHexta, nor can we find any 

 satisfactory answer. In other words, however useful for classification it undoubtedly 

 is to retain the enumerat(Hl names to designaf(^ the more diverse of these forms, it is 

 probable that both N. mndriana and A^ hnnedyi will eventually be considered only 

 striking variaticjns of A'', praclcxta. 



Found at station 451011, Gulf of California. 



Navicula silicula Ehrenb. Phys. Abb. Akad. Wiss. Berl. 1841: 419. 1843; Mikrog. 

 pi. 0. Lf. 16, pi. 10. Lf. IS, pi, Uj. 22, pi 15AJ. S7a-h. 1854. Pritch. Tlist. 

 Infus. ed. 4. 894. 18(il. 

 Navicula Umosa Ktitz. Bacill. 101. pi. S.f. 50. 1844. Grun. Verb. ZooL Bot. Ges. 

 W'wn 10: 544. pi S, f. 8a-c, 10 (not/ 7, 8d-e, 9). 1800. Donk. Quart. J(mrn. 

 Micr, Sci. n. s. 9: 294. pi 18. f. 7. 1809. Moeb. Diat.-taf. pi 79. f. 7. 1890. 

 Donk, Brit. Diat. 7:^. pi 12. f, 6. 1871 73. Brun, Diat. Alp. 73. pi 7.f, 12. 1880 



Van Heur. Synop. 103. pi 12. f. 18-20, 22-2S. 1881; Treat. Diat. 219. pi 5. f. 



207-208. 189G. Lagers. Bih. Sv. Vet. Akad. Handl. 1'^: \^\.pl. l.J. G, 7a. 1873, 

 Rabh. Sussw. Diat. 41. pi 6j, 31, 1853. Pritch. Hist. Infns. ed. 4. 894. 1801. 



De Tcmi, Syll. Alg. 2: 147. 1891. 

 Navicula silicula Grun.; Van Heur. Synop. pi 12. f, 21. ISSl. 

 Caloneis silicula Clove, Sv. Vet. Akad. Ilandl. 26'-: 51. 1894. 



« Jahresb. Komm. Deut. Meere 2: pi L / J.9. 1874. 

 & Loc. cit. 



