93 
Habitat.—Backstairs Passage, off Hog Bay, 16 to 18 fathoms, 
three valves; 20 fathoms, 17 valves; 22 fathoms, one alive, five 
valves ; depth not noted, seven alive, 295 valves ( Verco. ) 
Type specimens in my collection. 
Crassatella miera, sp. nov. Pl. i., fig. 3. 
Shell trigonally orbicular, rather compressed, equivalvular 
subequilateral, solid. Umbos acute, apposed, anteflected. Post- 
dorsal margin very short, at first convex, then almost straight, 
very rapidly descending ; front dorsal margin minutely excavated 
close to the umbo, then rapidly descending, almost straight; the 
two margins form rather more than a right angle with each 
other. Ventral margin acute, uniformly convex, about a 
quadrant, ascending roundly into the posterior margin, and 
rather more narrowly into the anterior. Lunule rather large, 
elongate-ovate, somewhat indistinct, left valve slightly overlaps 
the right. Escutcheon linear-lanceolate, edges rounded, right 
valve includes the left. Surface flatly convex, deeply concen- 
trically sulcated, seven ridges in the last three lines from the 
ventral margin, smooth, flatly-rounded, rather wider than the 
interstices, and not quite so high as wide. Internally, right 
valve, triangular cartilage pit behind a well-marked, triangular, 
cardinal tooth, in front of this is a short, vertical diverging tooth- 
like plate, in which ends the inner lamina of the anterior lateral 
tooth socket; anteriorly is a linear groove, most marked at its 
front end, where the inner lamina projects slightly ; the post- 
dorsal margin lightly projects in a tooth-like lamina ; left valve, 
triangular cartilage pit, behind two diverging cardinal teeth, the 
anterior of which is the more oblique, prominent and stout; 
base of lunule slightly prominent to form an anterior lateral 
laminar tooth; posteriorly a long linear groove, with barely 
visible projection of inner lamina beyond the level of the outer ; 
inner margin not denticulated. Color light-horn tint, some 
specimens white with horn-tint about the umbo. 
Dimensions, anterior-post diameter, 6 mm. ; umbo-ventral, 5:5 ; 
depth of closed valves, 2°5 mm. 
Habitat.—Backstairs Passage, St. Vincent Gulf, 8.A.; dredged 
20 fathoms, one alive ; 22 fathoms, one alive; dredge siftings, 
depth not noted, probably about the same, six alive, 184 valves 
(Verco). Type in my collection. 
C. fulvida, Angas, from Port Jackson, is allied, but is a trans- 
versely oval shell, being more produced anteriorly, much thinner 
and with proportionally fewer and stouter concentric ridges. 
