L.M.B.C. TURBELLARIA. 161 
the sub-family Hyporhynchinez) opens on the ventral sur- 
face, behind the anterior extremity, and is much reduced in 
size aS compared with that of the Acrorhynchine. The 
copulatory-organ consists of two spirally-coiled chitinous 
tubes fused throughout the greater portion of their lengths. 
Of these the finer duct transmits the granule-secretion, 
the wider one enables the spermatozoa to reach the 
exterior. The spiral takes two complete turns and ends 
in a terminal straight portion where the two ducts sep- 
arate from one another. 
This species was dredged in 15 fms. just outside Port 
Erin Breakwater. It has also occurred at Plymouth. 
Family—VoRTICIDA. 
16. Provortex balticus, Schultze (Pl. XIII, figs. 27, 28.) 
Length -5—°75 mm. Body cylindrical, truncated, in 
the angles produced into blunt processes. The posterior 
extremity forms a long, finely-pointed ‘‘ tail.” The colour 
is due to irregular brown pigment which appears to be 
deposited as fine vacuoles in the cells of the parenchyma: 
The pharynx which opens through the mouth just below 
the anterior end, is provided with a distinct ‘‘seam”’ to 
to the margin, furnishing a surface of insertion for the 
strong pharyngeal retractor muscles. 
The copulatory organ is cylindrical. Its aperture con- 
stitutes a slit, one margin of which is bent upon the 
main-duct and ends in a free process of variable shape. 
The uterus discovered by von Graff, hes in front of 
the penis and contains a single yellow cocoon at a time. 
A long fine duct leads to the genital aperture. 
This extremely active, tiny animal occurs plentifully in 
tide-pools near the Port Erin Station. It is also recorded 
from Millport and Plymouth. 
