282 BULLETIN OF THE 



A further study of these specimens, together with those of the Jeffreys col- 

 lection, has confirmed me in the opinion I expressed in my preliminary report 

 as to the remarkable variability of this species, the modifications being so grad- 

 ual that I am in doubt as to whether more than one species exists in our seas, 

 unless the P. sublcevis Verrill be different, as from the figure would seem likely, 

 if it be normal. P. neceroides has a surface similar to that of P. sublcevis, but 

 is at the opposite extreme of form. P. rotundata has a sparse or close granu- 

 lation indifferently, if one may judge by the few specimens I have seen. I 

 find among the specimens collected some small, inflated, and triangular, com- 

 pared with the average of the others, in which the granulation is composed of 

 beautiful minute spheres, perfectly transparent and closely set in quincuncial 

 arrangement with the greatest regularity. They agree in most details with 

 the description given by Smith of his australis. The granulation is coarser 

 than in the average granulata, and the effect of the light upon the transparent 

 spherules, under a glass, gives them the appearance of little cups or tubes. I 

 cannot feel positive that they are the same as the form described by Mr. Smith 

 without a comparison of specimens ; but they agree too closely to warrant 

 giving any other name to them until a comparison can be made. I have seen 

 one alcoholic specimen of P. granulata in which the soft parts showed no essen- 

 tial differences from Cetoconcha. The lower palpi were present and the siphons 

 not very long. 



Poromya (Cetoconcha) albida, n. s. 



Shell not pearly externally, white, thin, punctate and polished toward the 

 beaks, toward the margin with rather sparee granules covered with a thickish, 

 wrinkled, straw-colored epidermis ; beaks slightly nearer the anterior end, not 

 contiguous, rather high, small, inflated, but less so than in C tornata; both 

 ends rounded, the posterior a little less inflated and more produced; base 

 evenly rounded ; interior strongly radiately striate ; muscular impressions 

 high, narrow, impressed ; right valve with the hinge-line obtusely arched, the 

 centre under the beaks with a solid triangular thickening ; the anterior end 

 of this supports a stout, short, round-topped cardinal tooth, behind which the 

 callus supports on its dorsal surface a stout triangular cartilage, the anterior 

 end of which probably appears between the anterior bifurcation of the external 

 ligament, but the posterior apex of which is internal and covered by the liga- 

 ment ; the ligament, as in all this group, turns away from the hinge-line and is 

 lost under the beaks; above its course is an elevated narrow ridge which ex- 

 tends posteriorly to the end of and very close to the hinge-line. Lon. 21.5 ; 

 alt. 19.5 ; diameter of the valve 8.5, and of the whole shell probably 17.0 mm. 



A single right valve was obtained by the Fish Commission at Station 2159, 

 in 98 fms., near Havana, Cuba. The shell resembles Poromya suhlcevis Verrill, 

 but has twice or three times the size; otherwise, until the hinge is critically 

 examined it would pass for that species. It is, however, larger than any known 

 Poromya. 



