TRIBE MYTILACEA. 241 
M. Srriatura. Nobis Zool. Proc. 1844. Elongated-oblong, 
narrow, subarcuated, subcylindraceous, covered with an olive epi- 
dermis which is usually rayed anteriorly with narrow black streaks ; 
posterior side short, with three or four rather distant radiating ribs ; 
anterior side produced and rayed with most delicate striae, which at 
their extremity become slightly elevated and divaricate; interme- 
diate space smooth; dorsal margin scarcely elevated and very 
slightly convex, forming a very indistinct angle with the convex 
anterior which is nearly equal to it in length ; umbones depressed ; 
within purple, hinge crenated at the end of the ligament. Pailippines 
3.212. 
f °M. SoanAnaea Nobis Zool. P 1844, Elongated oblong, narrow, 
moderately ventricose, covered anteriorly with forked and subra- 
mose rather large and moderately distant depressed ribs, which on 
passing the very distinct (and in the young subcarinated) umbonal 
ridge, become fine strice, disappear and leave the posterior ventral 
side smooth ; hinge margin very short (crenated at its extremities 
withm) forming a distinct but little elevated angle with the anterior 
which is first incurved, nearly parallel with the ventral, and then 
slopes suddenly in a convex line to the incurved ventral, causing 
the compressed and produced anterior extremity to appear obtusely 
biangulated ; beaks narrow, incurved, all but terminal ; within, tin- 
ged anteriorly with purple. 2..14.—Mindinao. 
Section E. 
With radiating strie. No dorsal angle. 
M. Impacra.—Herman Naturf. 17. ¢. 3. f. 5 to 8.—D. p. 320. 
W. 4.12. f.40.—Myr. Austratis. Fabr.in Dankse V. S. S. 3. 
(1778 )—Ch. f. 768.—Myvr. Cor. Martyn U. C. t. 77.—( Born. 
vignette p. 121. D.) Moptora Discors. Lam. 16.—E. t. 204. f. 5. 
Oval, ventricose, under an yellowish olive cuticle of a reddish ash 
colour, a few distant rounded raised longitudinal sulci at the posterior 
end, and numerous grooves and very depressed costelle anteriorly ; 
intermediate area glabrous and very convex, with the ventral edge 
swelling out there; umbonestumid. 13—8S. Seas. 
M. Tumipa.*—M., Discors Macgyl. Ab. p. 239.—Twt. Biv. t. 
15. f. 4, 5.—Myrtitus Discors Mont. p. 167.—D. p. 319.—W. t. 
12. f. 39.— Turt. C. D. p. 112.—Da. Cos. t. 17. f. 1.—Poli. t. 13. 
Jf. 15.—Mop. Discrepans. Lam. 15.—Phil. p. 70 (from his onn 
specimen, certo) ‘The same general appearance as the last, but the 
epidermis light green, the posterior sulci numerous close and little 
raised, and the umbonal ridge more elevated. 4.—England. 
M. Discors. Sow. G.—Recve Syst. t. 100. f. 4.—Myrtitus. D. 
Lin. Sys. Ed. 12. p. 1159.—Fabr. Faur. Grenl.—Ch. f. 764. a. b. 
—Myr. D. var Arctica. Otho Fabr. Dankse V. S. Skriv. 3. t. Sake ol, 
4,6.—M. Lavicata Gray in Sup. to Parry—W. S, t. 2. f. 5. 
R 
