L.M.B.C. TURBELLARIA. 163 
lobster, but I have found them on the surface of weed- 
covered stones between tide-marks. 
This species is not uncommon in tide-pools at Port 
Erin, and is abundant at Millport and Plymouth. Young 
specimens occur in tow-nettings taken near shore. 
19. Vorticeros auriculatum,O.F. Muller (Pl. XIII. fig. 25.) 
Length 1:5—2 mm. Body elongate. The angles of the 
anterior margin are produced, in the expanded condition, 
into a pair of slender tentacles, almost '/; the length of the 
body. They may, however, completely disappear during 
contraction. The colour is due to violet, reticular, paren- 
chymatous pigment which occupies the dorsal surface 
(except the margins) and is continued as a narrow band 
over the upper surface of the tentacles. The anatomy 
resembles in detail that characteristic of Plagvostoma. 
This elegant form occurs in tide-pools at Port Erin. It 
has been taken by v. Graff at Millport, and myself at 
Plymouth. 
20. Allostoma pallidum,P.J.v. Ben. (P|. XIII, figs.31,32.) 
A few immature examples of this species occured at 
Port Erin. The anterior sixth is marked off from the rest 
of the body by a circular ciliated groove. The epidermis 
contains large numbers of ‘‘mucus-rods,’’ which have 
been considered as intermediate between the amorphous 
secretion of a subepidermal gland, and the sharply-defined 
rhabdites. All three are homologous, but differ in the 
degree of consistency. 
The common genital pore is almost terminal at the 
hinder end. The penisis muscular. It receives the vasa 
deferentia and granule-gland in its upper proximal portion. 
The oviducts (according to v. Graff), unite before opening 
to the exterior. This species has been recorded from 
Millport. 
