160 MR. H. CHARLTON BASTIAN'S MONOGRAPH 



rather narrow, moderately well covered with rather large particles having a tessellate 

 arrangement. Anus -yoiy" fi'om posterior extremity. Vulca near midtUe of body. 



Male, about same size as female. Anus about 2^" from posterior extremity. Spicules 

 rather short, curved, 43-5" 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 algae, whilst to the 

 posterior extremities of two specimens I have seen groups of Vortlcella attached. 



2. S. LiEVis, n. sp. (Plate XIII. figs. 201-206.) 

 Female, length ^", breadth ^oo"- 



External Characters. — Body light-coloured, tapering slightly anteriorly, and gradually 

 narrowing to a point posteriorly. Head most distinctly rounded. Integument smooth ; 

 no stria? visible ; a few small setae scattered over anterior extremity ; lateral cervical 

 depressions (slightly raised in centre) 3-^3^'' in diameter, close to anterior extremity. 



Oesophagus between -^gi\\ and ygtli of total length ; terminal swelling nearly globular. 

 Intestine sparingly covered Avith light-coloured hepatic particles having a somewhat 

 tessellate arrangement. Anus -xa~s' from posterior extremity. Vulva anterior to middle 

 of body, -x^" from anterior extremity. Uterus bifid ; segments symmetrical. Ova large, 

 occupying whole breadth of body. Genital tube containing large, spherical, finely 

 granular cells, about two " i^i diameter. 



Hale, length \", breadth -^". 



Oesophagus about 2^0^^ of total length. Anus xwr" from posterior extremity. Spicules 

 large, curved, 3-3-3" in length; accessory pieces straight, rather narrow, and half the 

 length of spicules. 



Sab. In sand from roots of small algae, tide-pools, Falmouth. 



3. S. TENUiCAUDATA, n. sp. (Plate XIII. figs. 207-209.) 

 Female, length yo", breadth a^r"- 



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 setae. Integument with transverse striae, pretty Avell marked, ^oloo " 

 apart ; two lateral circular depressions close to anterior extremity, 3^3-3" in diameter ; 

 when looked down upon, a small central circle is seen f rds less in diameter than that 

 which contains it. 



(Esophagus about ^th of total length ; posterior enlargement not nearly globular. 

 Intestine covered pretty uniformly with pale small-sized granules. Anus ixz" from pos- 

 terior extremity. Vulca about middle of body. 



Male, length ^", breadth 3^" ; having a few short setae scattered over posterior 

 extremity. Anus x^x' fr'om posterior extremity. Spicules narrow, curved, 5-5^" long ; 

 accessory pieces reflexed, curved, almost linear, -q^" long. 



Hab. In sand from tide-pools, Falmoutli. 



The different shape and length of the oesophagus, as well as the difference in form of 

 the spicules and accessory pieces, lead me to suspect that this species will hereafter re- 



