428 bulletin: museum of comparative zoology. 



Verticordiidae. 



LYONSIELLA Sars. 



Lyonsiella paciflca Dall, n. Bp. 



Shell small, plump, white, subquadrate, microscopically radiately closely grauu- 

 lately striate, covered more or less densely with adherent sand grains and forani- 

 inifera ; beaks large for the size of tlie 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. 

 Lou. 3 ; alt. 2.7; diam. 1.8 mm. 



U. S. S. "Albatross," station 4693, Mid Pacific, northwest point Salay Gomez 

 Island, bearing N. 82° E., fifteen miles, in 1142 fathoms, gravel, bottom tempera- 

 ture 35°.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 L. papyracea Smith, figured in the " Challenger " 

 Report, but the sculpture is quite difi"erent 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. 

 PORO.TIYA Forbes. ■ 



PoTomya Forbes, Aegean Rep. Brit. Assoc, 1844, p. 103; type, P. anatinoides 

 Forbes, /. c, = P. grannlata Nyst (as Corlnda). 



Embia Lovcn, Ind. Moll. Scand. Occ, 1846, p. 46; type, E. korenii Loven {=■ grauu- 

 lata Nyst). 



Ectorisma Tate, Trans. Roy. See. Austr., 1002, 15, p. 127, pi. 1, fig. 3; Hedley, 

 Proc. Lin. Soc. N. S. Wales, 1906, p. 5-39 ; type, E. granuhta Tate (not of 

 Nyst). Hedley, Rec. Austr. Mus., l'.)07, 6, p. 302, makes Tate's species prob- 

 ably identical with Poromya laevis Smith, of the " Challenger " Report. 



Poromya perla Dall, n. sp. 



Plate 18, flRures 2, 5. 



Shell small, globose, exceedingly thin, whitish, subequivalve, subequilateral, 

 with very high swollen, strongly prosococlous beaks; no lunule or escutcheon, 

 but the posterior hinge margin of the right valve overlaps that of the left, witli a 

 single, strong, radial rib near the edge, wliich does not appear in the opposite 

 valve; anterior margin of the valves evenly rounded into the nearly semicircular 

 b.isc ; posterior slope straight ; posterior end short, somewhat compressed and 



