TETHYS—EUROPEAN. 69 
I. Species of European Seas. 
a. Swimming lobes united behind as far up as the excurrent siphon ; 
mantle having a wide median orifice exposing the shell, its 
edges not thickened. A group of unicellular glands each with 
independent duct in place of the opaline gland 
depilans, punctata. 
aa. Swimming lobes free to their union with the fout behind ; man- 
tle having a median minute perforation or a little tube. 
6. Opaline gland with multiple ducts; green; length 27 em. 
lobiancot 
6b. Opaline gland grape-bunch like, with one duct. 
c. Length 12-20 cm.; very dark, sometimes flecked with 
light leporina 
ce. Length 6 cm.; obscure green, marbled with black 
marmorata 
ccc. Pale yellowish with scattered black rings dactylomela 
fT. DEPILANS Linné. Pl. 23, figs. 26, 27; pl. 24; pl. 33, fig. 25. 
Length about 20 em. Shorter and more compressed than T. lep- 
orina. Swimming lobes united behind as far forward as the mantle 
siphon; foot rounded posteriorly. Mantle or gill-cover with a 
broad round orifice leading into the shell-cavity, and surrounded by 
dark brown rays. On the under side of mantle edge the numerous 
glands secreting a milky fluid (homologous with the purple glands _ 
of T. leporina) open. Siphon of the mantle shorter than in lepo- 
rina; genital and anal openings as in /eporina. Behind the genital 
opening there are numerous one-celled glands each with its separate 
opening, in place of the grape-bunch like gland of leporina (pl. 33, 
fig. 25). 
Color extremely variable ; generally the ground is light brown, 
often gray-brown, rarely quite dark, always with white or light 
gray spots with irregular outlines. Shell similar to that of leporina, 
but with stronger calcareous layer. 
Mediterranean and Adriatic Seas; Atlantic: Torbay, 8. coast 
Devon, England, and Channel Is.; W. coast of France, Madeira, 
(? and Cape of Good Hope). 
Laplysia depilans L., Syst. Nat., 12, p. 1082, founded mainly on 
Lernea of Bohadsch, de quibusdam animalius marinis, etc., pl. 1-3. 
—Baresvt, The Gen. Vermium, p. 31, pl. 3, f.5,6.—Brua., Encyel. 
Méth., pl. 83, 84 (copied from Bohadsch).—Lam., An. s. Vert., PEN- 
