136 MR. H. CHARLTON BASTIAN’S MONOGRAPH 
Hab. Amongst half-tide sand and stony débris very abundant, and also found One — 
on a bright grass-green filiform weed (free from Diatomaceæ) from tide-pool, Falmouth, 
2. O. GLABER, n. sp. (Plate XI. figs. 129, 130.) 
Female, length 45", breadth 545”. 
External Characters.—Body tapering slightly forwards, but considerably towards 
posterior extremity, which is long, narrow, and pointed, and terminates with a minute 
sucker. Head rounded, naked. Integument plain or with longitudinal markings. 
Pharyngeal cavity yess" long. Œsophagus about ith of total length, embraced ob. 
liquely, near its middle, by an wsophageal ring. Intestine thinly covered with hepatic 
particles. Anus 135° from posterior extremity. Vulva about middle of body. Evere- 
tory ventral duct ...... 
Male, not seen. 
Hab, Marine surface-mud from estuary, Falmouth. 
3. O. viscosus, n.sp. (Plate XI. figs. 131-133.) 
Female, length 45", breadth 1”. 
External Characters.—Body long and filiform, scarcely at all narrowed anteriorly, 
but tapering gradually to a point at posterior extremity, which terminates with a minute 
sucker. Head bluntly rounded, provided with a circlet of four setæ. Integument 
plain or with longitudinal markings, having numerous fine particles of sand and diatoms 
adhering to its external surface. 
Pharyngeal cavity yy" long. Œsophagus 1th of total length, embraced obliquely, 
near its middle, by an esophageal ring. Intestine sparsely covered with hepatie par- 
ticles. Anus 555" from posterior extremity. Vulva at middle of body. Uterus 
bifid. 
Male, the same length as female, breadth sis 
Anus 335" from posterior extremity. Spicules solitary, of an elongated wedge-shaped 
form, and 1455" long. 
Hab. Marine surface-mud from estuary, Falmouth. | 
When a thin layer of mud is spread out with water on a slip of glass, I have met 
with this species generally floating on the surface, appearing under a hand-lens as à 
slowly moving pellucid filament. 
4. O. FUSCUS, n.sp. (Plate XI. figs. 139, 140.) 
Male, length +", breadth 414". 
External Characters.—Body stout, of a brownish colour, tapering slightly forwards, 
but abruptly posterior to anus. Terminal sucker minute. Head narrow, rounded, 
having a circlet of 6-8 short, thick setæ at 1350 from anterior extremity. Integument 
M € longitudinal markings; slightly tinged of a blackish colour at posterior ex- 
remity. 
Pharyngeal cavity 41," long, large, elongated-oval ; one tooth. much larger than 
either of the other two. Œsophagus about lth of total length; slightly enlarged pov — 
nv: Lp: ving visible. Intestine thickly covered with dark-brown hepatic particles; 1 
‘tessellation indistinct, Anus 54 from posterior extremity. Spicules long and narrow, | 
