74 THREE CRUISES OF THE “BLAKE.” 
largest known species being one of the “ Blake” treasures, V. 
elegantissima Dall (Fig. 308), a 
brilliant pearly shell; one of the 
smallest is V. perversa Dall (Fig. 
309), which has the larger bulge 
in front of the hinge, contrary to 
the usual rule. 
A lovely new group related to Thracia and Anatina is repre- 
Fig. 307. — Cuspidaria mierorhina. 4. 
Fig. 309. 
a Verticordia Fig. 310. — Bushia ele- 
Fig. 308. — Verticordia ele- perversa, 2, gans, 4 
gantissima, 1. 
sented in deep water by a single species, which has been named 
Bushia elegans. (Fig. 310.) 
We may also mention, as evidently a deep-water group, the 
shells of the subgenus Meiocardia, re- 
lated to Jsocardia cor of Europe. 
These are remarkable for the way in 
which the tips of the valves are 
twisted and turned away from each 
other. ‘They are common tertiary 
fossils; but only a few living 
Fig. 311.— Meiocardia Agas- species are known, and, excepting 
af E Isocardia cor, these are tropical. 
The dredgings of the * Blake” and the “ Albatross” have re- 
vealed a new Meiocardia in the Antilles, the others being all 
Oriental, and this has been named M. ‘Agassizii. (Fig. 311.) 
À new group, differing from Isocardia and Meiocardia in hav- 
ing no lateral teeth, is Vesicomya, previously unknown from 
American waters, the largest known species of which is a form 
now named V. venusta (Vig. 312), from Antillean specimens. 
A much smaller species, named V. pilula, is reported by the 
