eal ici. Saeet less c 
Fe iment, anterior end more atte! 
’ es s - conspicuous than in minima; lun 
: _ Cal., ‘to Point Obreojos, SS Cal.; 
ane ; extremely s nall. 
sr V Haliotis, eee 
‘ed - 0102 Thyasira enue Dall. “Alaska. . ee 
dea ‘ ee ape 
21: 0103 Thyasira tricarinata Dall. oft S. Baroda Isl., Sts Oe 
fathoms. As 
Shell chalky white, produced Below, with pointed. prosocoe! 
ous beaks over a deeply impressed ovate lunule bounded by a 
sharp carina; escutcheon long, narrow, lanceolate, the valve mar- 
gins rising as a sharp keel in the middle, the outer border very 
prominetly keeled, outside of which is a similarly shaped exca-_ 
vated area also bordered by an angular keel; still outside of this Bee. 
there is a compressed area with no distinct anterior boitaies Ds 
except an obscure ray near the umbones; over this area the sur- ts 
face is concentrically striated, the rest of the disk being ef. a 
smooth; hinge very feeble, ligament linear; length 15, ait das 18, 
diameter 10 mm. 
21: 0104 Erycina catalinae ‘Dall. Catalina Isl., Cal. 
ae. Shell small, inequilateral, the anterior side shorter, rounded, 
the base nearly stf@ight; posterior side also rounded, slightly | : 
attenuated, dorsa e convex but descending; hinge strong, — etch 
teeth well prem ped; eaks. well developed,-not prominent, sur- ; ee 
ihe * face smooth ex e Tor. faint incremental lines, covered with a “phe ae 
iy light yellowish- brown dull nee acum; length 2.5, height 2, di-  — 
ameter 1.3 mm. ' | veal ee 
21:0105 Erycina? coronata Dall. Off So. Coronado Isl., Cal. ae 
Bar Shell small, white, rounded quadrate, nearly equilateral, the’: =a 
surface finely concentrically striated; basal margin nearly straight; * 
- ends rounded, the posterior a little produced basally, the dorsal 
slopes Simlar, slightly descending, with at each end 2-4 minute 
elevated spinules; length 4, height 3, diameter 1.2 mm. Only | 
one left valve was obtained by Dror, Baker. ; 
21:0106 Erycina bakeri Dall. Off-So. Coronado Isl., Baja Cal. 
Shell small, white with a pale yellowish periostracum, sub- ~ 
quadrate, inequilateral, the anterior end shorter; hinge line 
short, straight, at the outer extremities usually a small spinule, 
beaks pointed, the prodissoconch visible; from the beak extends 
a wide depression obliquely backward .to middle of base, becoming 
more defined distally; at base in adult it is strongly marked and 
- emphasized by a rounded sulcus in margin, behind which the 
surface rises into a rounded ridge armed with one .or more ele- 
vated short lamellae, and having its basal termination produced 
into a sort of a hook; hinge rather feeble, valves father. com- 
pressed ; length 6.3, height 4.5, diameter 2 mm. . 
mab 
J N pee 
21:0107 Erycina batlinwe Dall. Off So. Coronado I., Cal. Sy 
Shell small, with the outline of a very compressed Kellia, — Bs 
white with a very pale yellowish periostracum, concentrically mi- 
croscopically threaded, the threads occasionally becoming micro- 
scopically lamellar; valves nearly equilateral, anterior part slightly 
longer, base evenly arcuate, posterior end somewhat attenuated; 
