SOME NEW AND RARE DIATOM* 



occupying three-fifths the diameter <>f the valve, coarsely areolated with hexagonal cells ; outer 

 part coarse and irregular in areolation; entire surface punctate, puncta arranged in radiant lines. 

 Habitat. Sandwich Islands; W. C. Walker. Plate I. Fig. 1. 



This exceedingly beautiful species of Biddulphia is well figured in our illustration, and is 

 very large: it belongs to tlie subdivision of which B. favus is the type, a> is evidenced 

 by the corrugated border and radiant punctation ; the central circular portion, which is much de- 



■ d from the surfacedevel of the remainder of the valve, suffices to at once place it as an en- 

 tirely new species; several examples having been observed by Mr. "Walker. 



Biddulphia fbrmosa, var. neiitagonali*, Witt. Valve large. 5-angled. angles 

 slightly rounded: processes smooth, prominent : cellulation radiant, being that of B. formma ( Tri- 

 ceratium) except that near the margin the cellules suddenly grow smaller: processes smooth. 

 Diameter between angle- .0037 inch. Habitat. Pacific Soundings. Plate 2. Fig. 9. 



This species is figured in Schmidt's Atlas, plate 79, f. 4: the figure in our plate is from a valve 

 in our possession : as several valves have been noticed, we think the variety is one that will be 

 sustained. 



Biddulphia creillllata, X. Sp., W. C. Walker. Valve large, circular: margin cre- 

 oated and striate: from 4 to 8 prominent mesi circular processes, which are intra-rnarginal and 

 smooth; surface of valve finely punctate, puncta in radiant rows. Diameter of valve .004 inch. 



Habitat. Challenger Sounding, No. 287. Pacific Ocean. W. ( '. Walker. Plate 2, Fig. 7. 



Quite a number of valves of this interesting and beautiful species have been found by Mr. 



Walker, in one of the Challenger Soundings: in accordance with the views of the most advanced 

 students we place this as a Biddulphia, to which Genu- the vast majority, if not all of the mem- 

 j of the Genus Triceraiium will be relegated: the new genera " Lampriscus " and •• Odontella- 

 Lamp Grunow, must be condemned. 



\ m phi prom cormita. X. Sp., H. II. Chase Valve large, .0063 inch in length, by 

 .0033 inch wide: deeply constricted at centre : extremities round, bearing a large, round, smooth. 

 prominent process; striation very fine, extending two-thirds the distance to the centre, leaving an 

 oval, smooth space in the middle of each lobe; margin strongly banded. Habitat. Tuscarora 

 Sounding, 2,240 fathoms, Pacific Ocean. II. II. Chase. Plat.- I. Fig. 6. 



A very peculiar Diatom, and one very diflficull t<> classify, but the twisted keel.- seem to de- 

 termine that it should be placed in the Amphiprora ; the oculi at the extremities are quite similar 

 to those of AuMscus ; the striation is very line, being 55 in .001 inch. 



\ lliphiplciira maxima, X. Sp.. Jl. L Smith. Structure and general characteristics 

 thoseof Amphipleura ; length of valve. 0146 inch: striae 80 in. 001 inch. Habitat. Fossil deposit. 

 Klakamas. Oregon. Plate 2. 1- ';. 



