160 MR. H. CHARLTON BASTIAN’S MONOGRAPH 
rather narrow, moderately well covered with rather large particles having a tessellats 
arrangement. Anus z45 from posterior extremity. Vulva near middle of body. 
Male, about same size as female. Anus about 5345 from posterior extremity. Spicules 
rather short, curved, 435° in length; accessory pieces short, horizontal; proximal 
extremity curved and pointed. 
Hab. Amongst sand and small stones from tide-pools, Falmouth. 
Body often more or less covered with minute tufts of hair-like algæ, whilst to the 
posterior extremities of two specimens I have seen groups of Vorticella attached. 
2. S. LæÆvis, n. sp. (Plate XIII. figs. 204-206.) 
Female, length +”, breadth 54>”. 
External Characters.—Body light-coloured, tapering slightly anteriorly, and gradually 
narrowing to a point posteriorly. Head most distinctly rounded. Integument smooth ; 
no stri visible; a few small setze scattered over anterior extremity ; lateral cervical 
depressions (slightly raised in centre) 3343” in diameter, close to anterior extremity. 
(Esophagus between sth and 45th of total length; terminal swelling nearly globular, 
Intestine sparingly covered with light-coloured hepatic particles having a somewhat 
tessellate arrangement. Anus 355" from posterior extremity. Vulva anterior to middle 
of body, 75” from anterior extremity. Uterus bifid; segments symmetrical. Ova large, 
occupying whole breadth of body. Genital tube containing large, spherical, finely 
granular cells, about 1455" in diameter. : 
Male, length +”, breadth 41". 
Esophagus about th of total length. Anus 41 i from posterior extremity. Spicules 
large, curved, 335" in length; accessory pieces straight, rather narrow, and half the 
length of spicules. 
Hab. In sand from roots of small algæ, tide-pools, Falmouth. 
3. S. TENUICAUDATA, n. sp. (Plate XIII. figs. 207-209.) 
Female, length 355", breadth 41z". 
External Characters.—Body white, tapering gradually anteriorly, but more abruptly 
towards posterior extremity, which is long and filiform. Head truncate, provided with 
a circle of 4-6 setze. Integument with transverse strive, pretty well marked, 55600 
apart; two lateral circular depressions close to anterior extremity, 3353 in diameter; 
when looked down upon, a small central circle is seen $rds less in diameter than that 
which contains it. 
(Esophagus about ith of total length; posterior enlargement not nearly globular. 
Intestine covered pretty uniformly with pale small-sized granules. Anus 413" from pos 
terior extremity. Vulva about middle of body. 
Male, length +’; breadth 335 ; having a few short setæ scattered over posterior 
extremity. Anus 44” from posterior extremity. Spicules narrow, curved, soo 1008; 
accessory pieces reflexed, curved, almost linear, gt,” long. 
-Hab. In sand from tide-pools, Falmouth. 
The different shape and length of the cesophagus, as well as the difference in form of 
the spicules and accessory pieces, lead me to suspect that this species will hereafter 2% 
