294 CONTRIBUTIONS FROM I Ml NATIONAL HERBARIUM. 



Trigoiiium plano-ooncavum Brun Mann 



"m Brun in Bfud & Temp. Mem. Soc. Phye i i Hist. Nat 

 ■ •• I K 1889 Brun, Le Diatomiste 1 : •». /#/. i. /. i. L890 



De Toni, Syil. Alg. 2: 929. 1894. 

 I »•■ Toni notes the resemblance of this Bpeciee to /'. inelegant Grev., a / nicoba 

 Grun.,& and T. juncalenm Grun.< The Bimilarit) exists hut is slight, especially ii 

 examined with high magnification and slightly oblique light, bj which means the 

 remarkable pitting of the beads brought out in the fine photograph in Le Diatomiste i- 

 made plain. 



Pound at stations 3688H, 1029H, Galapagos Islands and Okhotsk 8< 



Trigonium rusticum Mann, sp. nov. I'i \ii I.I. not i;i I 



Valve triangular, slightly convex; the angles extended into Bat arms with slightly 



broadened ends; sides between the arms inflated; markings coarse, consisting of a few 



scattered oval beads at the center of the valve, thence outward strictly radiating, 



decreasing in size i" the margin, which is very narrow and most minutely beaded; a 



minute spine at the apex of each arm. 



Width between the apices, 0.06 nun. 



It resembles remotely T. microcephalum Grev.d and '/'. subcapitatum Grev.< but 

 differs materially in it- coarse, b1 ronglj radiating beading and especially in its Oat arms 

 destitute of the globose elevated ends found in the foregoing. 



Type in the U.S. National Museum, No. 590134, fromstation W29H, Bering Sea, June 

 27, 1900; 913 fathoms, bottom of gray sand and clay. 



Trigonium sculptum (Shadb.) Mann. 



/ iceratiwm reticulum Bright. Quart. Journ. Micr. Sci. 1: 251. pi. ■',./. 17. I v "' 

 not Ehrenb. 



eratium sculptum Shadb. Trans. Micr. Sue. Lond. n. s. 4: r>. pi. l.j. .;. L854. 

 Moeb. Diat. taf. pi. .;./?.;. L890. Schmi.lt. Atlas pi. 76. f. 9 i.\ SI. L877, pi. 

 150. f. 17. L890. Van Heur. Synop. pi. 109. f. : 8, pi. in./. 8. L881. Pritch. 

 Bist. Infus. ed. I. 856. L861. Wolle, Diat. N. A. pi. 106./.S 5, pi. 111. f. .. 

 L890. Petit, Fonds de La Mer 3: L95. L877. 



eratium punctatum Bright. Quart. Journ. Micr. Sci. 4: 275. pi. 17./. 18. L856. 

 Pritch. Hist. Infus. ed. 4. 856. pi. 6. f. 10. L861. De Toni, Syll. Alg. 2: 944. 

 L894. II. I. Smith, Sp. Diat. Typ. qo. 602. L874. Cleve, Bin. Sv. Vet. Akad. 

 Han. II. 5 8 : I'i. L878. Van Heur. Synop. pi. 109.f.6,9 10. L881. Wolle, Diat. 

 N. A. r l. mi./. !>. n. L890. Schmidt, Atlas pi. 76. f. 19 .<>. L882; pi 

 L885; pl.99.f.5. L886. Cleve in Nordensk. Vega Exped. 3: 503. L883. Petit, 

 Fonds de laMer3: L94. L877. 

 Biddulpkia sculpta Van Heur. Synop. 208. I s ^~>. 

 Trin nihil,, i parentis Schmidt, At la.- pi. 79. f. 15. L882. 

 Biddulpkia reticulum Boyer, Proc. Acad. Phila. 1900:71' I. L901. 

 This species varies greatly. It is common to find in the Pacific dredgings forms 

 with a small curved spine in the center and an evident bul delicate circular ridge, 

 centrally placed, having a radius of one-half the distance from center to side of the 

 valve. Schmidt ' mentions the .-pine, saying there are one to three in form- from 

 Nottingham, Maryland; but he does not mention the ridge. Shadbolt gives emphasis 

 to three minute rings near the center. These, like the ridge and Bpines mentioned, are 



a Trans. Micr. Soc. Lond. n. s. 14: 8. pi. .'../'. .'/. L866. 



''Schnu.lt. Atlas pi. 76. j. It. L877. 



'Schmidt. Alia- j>l. 76. f. IS. L877. 



dTrans. Micr. Soc. Lond. n. .-. 9: 7 1. r l. .•'../. ;. L861. 



< Quart. Journ. Micr. S.-i. n. b. 3: 234. pi. 10. j. 0. L863. 



/Schmidt. Alia- pi. 76. f. :>■. L882, 



