428 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY, 
Verticordudae. 
LYONSEELLA Sars. 
Lyonsiella pacifica Darı, n. sp. 
Shell small, plump, white, subquadrate, mieroscopically radiately closely granu- 
lately striate, covered more or less densely with adherent sand grains and foram- 
inifera; beaks large for the size of the shell, high, prosogyrate with a small 
cordate impressed area in front of them; anterior end very short, small, posterior 
longer, wider, rounded ; base arcuate, prominent in the middle ; no external liga- 
ment; surface closely covered with radial rows of extremely minute granules. 
Lon. 3; alt. 2.7; diam. 1.8 mm. 
U. 8. 8. “ Albatross,” station 4693, Mid Pacific, northwest point Sala y Gomez 
Island, bearing N. 82° E., fifteen miles, in 1142 fathoms, gravel, bottom tempera- 
ture 359.4 F. U.S. N. Mus. 110,583. 
Only a single specimen of this finely granulose species was obtained. In form 
it is not unlike the much larger Z. papyracea Smith, figured in the “ Challenger " 
Report, but, the sculpture is quite different and the shell is proportionately more 
compressed. It is impossible to determine whether the specimen is adult or not, 
but it has a mature aspect. 
Poromyacidae. 
POROMYA Forges. 
Poromya Forbes, Aegean Rep. Brit. Assoc., 1844, p. 103; type, P. anatinoides 
Forbes, l. c., = P, granulata Nyst (as Corbula). 
Embla Lovén, Ind. Moll. Scand. Occ., 1846, p. 46; type, E. korenii Lovén (= grant 
lata Nyst). 
Ectorisma Tate, Trans. Roy. Soc. Austr., 1902, 15, p. 127, pl. 1, fig. 3; Hedley, 
Proc. Lin. Soc. N. S. Wales, 1906, p. 539; type, Æ. granulata: Tate (not of 
Nyst). Hedley, Rec, Austr. Mus., 1907, 6, p. 302, makes Tate’s species prob- 
ably identical with Poromya laevis Smith, of the “ Challenger ” Report. 
Poromya perla Darı, n. sp. 
Plate 18, figures 2, 5. 
Shell small, globose, exceedingly thin, whitish, subequivalve, subequilateral, 
with very high swollen, strongly prosocoelous beaks; no lunule or escutcheon» 
but the posterior hinge margin of the right valve overlaps that of the left, with Y 
single, strong, radial rib near the edge, which does not appear in the opposite 
valve; anterior margin of the valves evenly rounded into the nearly semicircular 
base; posterior slope straight; posterior end short, somewhat compressed an 
