M2 RUNCINA. 
Two very small species are known. They have the general aspect 
of the Limapontias, but are readily distinguished on superficial ex- 
amination, by the gill. 
R. CORONATA Quatrefages. Pl. 68, figs. 31-41. 
Animal presenting a smooth body covered with vibratile cilia; 
mantle quite convex, visibly emarginate in front, extending a little 
on the sides, incompletely covering the foot, rounded behind; color 
black, with minute brown dots, except in front and at the hind end, 
where it is a more or less light fawn tint. Eyes sunken in the in- 
tegument, rather large, each surrounded by a pale stripe; behind 
the eyes there is usually on each side a curved line of little white 
spots, forming a sort of continuation of the light colored frontal re- 
gion. 
Foot yellowish (pale ochre), sometimes marked with black spots 
or flames; its forward margin is perceptibly concave ; sides nearly 
parallel, and towards the head it is slightly wider than the mantle; 
tail end extending beyond the mantle about a fourth the length of 
body, 
The semipinnate gill is composed of 3 or 4 little plates, and pro- 
jects slightly behind the dorsal integument on the right side (see 
fig. 39). 
Formula of teeth 1.1.1; jaws triangular, wide, formed of little 
chitinous pieces of more or less polyhedral form, well separated from 
each other. Gizzard with 4 equal cartilagino-caleareous pieces (pl. 
68, figs. 38, 34). 
Length of animal, 4 to 5 mill. 
Bréhat Island, off N. Brittany (Quatrefages); Torbay, England 
(Alder & Hancock) ; Belmont Bay, near Weymouth (Thompson) : 
Clyde district (Norman) ; Gulf of Marseilles (Vayssi€ére). 
Pelta coronata QUATREF., Ann. Sci. Nat. (3), i, 1844, p. 151.— 
VAYSSIERE, Ann. Sci. Nat. (6), xv, 1883, p.6, pl. 1, f. 1-12; pl.2, fi. 
13-21; Rech. Zool., Moll. Opistobr., Tectibr., p. 104, pl. 5, f. 126- 
129.—Pelta ornata QUATREF., t. ¢., p. 152.—Pelta or Limapontia 
AupEeR & Hancock, Ann. Mag. Nat. Hist., xviii, November, 1846, 
p. 289, pl. 4, f. 1-7.— Runcina hancocki Forses, Hist. Brit. Moll., iii, 
p. 612, pl. CCC, f. 2—Gray, Guide Syst. Dist. Moll. B. M., p. 205, f. 
114 (dentition).—H. & A. Ad., Gen. Ree. Moll., ii, p. 43, pl. 61, f. 5. 
—-JEFFREYsS, Brit. Conch., v, p. 15, pl. 1, f.3.—Pelta nigra “Alder & 
