VOL. x\n 

 i89;j. 



] PROCEEDINGS OF TPIE NATIONAL MUSEUM. 311 



Synedra pulchella Kg. (N'aii lleurfk's Syu., i>I. 11, iigs. 1-8.) Fie<[uent. 



Synedra ulna Khib. (Vau lUiiirck'.s Syii., pi. 38, fig. 7.) Scarce. 



Synedra ulna, var. subeeqiialis Giuu. (Van Ileurck's Syn., pi. 38, fig.l3.) Scarce. 



This, put as a doubtful species by Van Heurck, is, as lie suggests, 

 only a variety of itbia. 



Synedra ulna, var. spathulifera Grun. (Van Heurck's Syu., pi. 38, fig. 4.) Scarce. 

 The same is true in this case also. 



TabeUaria fenestrata Kg. (Smith's B, D., pi. 43, fig. 317, p. 4fi.) Common. 

 Triceratium acutum p]lul». (Van Ileurck's Syn., pi. 108, fig. 1.) Scarce. 



This genus, uuule up principally of triangular and quadrangular 

 forms of Bi(}<lulphia, is so heterogeneous in character that it should be 

 abaudoned, its Prof. 11. L. Smith suggests, and its forms assigned to 

 their proper scientihc; geneni. 



Triceratium alternans Ehrb. (Schmidt's kihm, pi. 78, figs. 9-17.) Very common. 

 Triceratium bicorne Cleve. (Schmidt's Atlas, pi. 78, figs. 24-25.; Cleve's W. India 

 Diat. 1)1. 5, fig. 30, p. 17.) Very scarce. 



This diatom is an evident Biddnlphia, as was suspected by Cleve 

 when he named it. In general appearance it is much like the abnor- 

 mal B. reticulata figured in Schmidt's Atlas, pi. 78, fig. 21; but under 

 high magnification it fails to show the reticulating secondary markings 

 characteristic of that species. 



Triceratium cinnamomeum Grev. (Moebius's Plates, pi. 47, fig 12 ; Schmidt's Atlas, 

 pi. 151, figs. 23-27; Van Ileurck's Syu., i)l. 120, fig. 1.) Very scarce. 



The specific name is variously spelled cimamomeum, cinnamoneum, 

 and as above. Van Heurck includes it in Cestodiscus, to which it pre- 

 sents doubtful analogies. 



Triceratium inelegans Grev. (Moebius's Plates, pi. 71, fig. 21; Van Heurck's Syn., 

 pi. 110, figs. 2-5.) Connuon. 



See note under T. punctatum. 



Triceratium ornatum Shad. (Moebius's Plates, pi. 16, figs. 10-14; Schmidt's Atlas, 

 pi. 98, figs. 7-13.) Scarce. 



This is Wallisch's AmphUetras pentacrinus, and is essentially the 



same as T. biquadratum Janisch, T. junctum A. S., T. Balearicum 



Cleve, and a large number of unimportant varieties, as ^^yrt, hirsuta,^^ 



in Challenger Exp., pi. 2'S, tig. 9. This diatom is remarkably variable, 



even hi a single gathering, Avhich is probably the reason for the num- 



ber of pseudonyms created for it. The name '-'■pentacrinus^^ is deceptive. 



Triceratium punctatum Bright. (Moebius's Plates, pi. 9, fig. 18. Van Heurck's 

 Syn., pi. 109, figs. G, 9-10.) Very common. 



The strict types of both this aud T. inelegans^ Grev. are found in this 

 gathering and many intermediate forms, which make it evident that 

 these two close species are merely varieties of <me. Though the name 

 '■'• inelecjanH^^ is not well chosen for these forms, it should be preferred 

 to ^^ punctatum, ^^ as Wallisch has applied the latter to a wholly different 

 diatom. See Moebius's Plates, 31, tig. 21. 



