MUSEUM OF COMPARATIVE ZOOLOGY. 305 
Myonera laticella, n. s. 
Shell large, thin, inflated, rather short, white with a pale brown epidermis; 
beaks full, prominent, their apices touching over the cartilage; right valve a 
little the larger; sculpture of concentric, elevated, thin, but not sharp-edged 
lamellez, more distant on the beaks, higher and more crowded toward the basal 
margin, failing at the anterior boundary of the rostrum where they are repre- 
sented by the fine incremental strix, if at all; radiating sculpture consisting 
of somewhat irregular distant sharp elevated lines, which are most abundant 
between the middle of the shell and the rostrum; these rise up under but do 
not cut through the concentric lamelle, which by them are thrown into waves, 
like loose cloth lying over several cords stretched taut, which waves grow 
obsolete toward the base; there are also extremely fine radiating striations on 
the smooth rostral areas, which are bounded by an imaginary line extending 
obliquely from the beaks to the lower extreme of the rostrum; these striations 
bear elevated lines of epidermis ; there is a very narrow depressed area along 
the cardinal margin behind the beaks; the margin of the right valve fits over 
the posterior part of the rostral margin of the left valve; the rostrum itself is 
short, slightly recurved and obliquely rounded off from below, and in a less 
degree from above, to form a gaping rounded tip; the hinge-line is simple, with 
a rather large posteriorly directed fossette for the cartilage in each valve, and 
without buttresses; the cartilage is reddish brown, and carries a subrectan- 
gular ossicle; approximate length of shell (broken) 20.0; of young shell (taken 
from lines of growth) lon. 8.0, alt. 5.0, diam. (about) 5.0mm. From the tip 
of the rostrum to the beaks at the cartilage measures in the adult 13.5 mm., 
and the diameter when perfect must have been at least as much. 
Habitat. Near Curacoa, at U. 8. Fish Commission Station 2126, in 1701 
fms., yellow mud, bottom temperature 39°.3 F. One living but broken speci- 
men of which the base and anterior end were gone. 
This very elegantly sculptured species is so different from any of those 
described that I felt justified in characterizing it from the imperfect specimen. 
Apart from its sculpture it somewhat resembles M. undata Verrill in general 
form, though the rostrum in that species is shorter and the fossette propor- 
tionally smaller. 
Famiry ANATINIDZ. 
Gexus PERIPLOMA Scuumacuer. 
In the region covered by the investigations of the “Blake” several species of 
this genus are indigenous. P. ineequivalvis, the type, is often found on sandy 
beaches, but usually only the convex valve, destitute of its ossicle. The most 
common species on our Southern coast is the P. angulifera Phil., described 
VOL. XII. — NO. 6. 20 
