TURBELLARIA OF PLYMOUTH SOUND. 35 
armatus (Z), H. (2) penicillatus (Z), Provortex affinis (N), 
P. rubrobacillus (Z). 
AtL@ocata, Plagiostoma vittatum (N and Z), P. dioicum (N), 
P. girardi (N), Monotus albus (N). 
New Grounds. 
The Turbellaria of this part of the Sound (north of the west 
entrance to the Sound), like the flora, is similar to that of the Duke 
Rock. ‘There is, however, a characteristic form (Provortex rubro- 
bacillus) that has not occurred elsewhere in the neighbourhood. 
Macrorhynchus croceus and M. helgolandicus will probably be found 
in other parts of the Sound, although at present this is the only 
known locality for them. 
Polycladida, Leptoplana tremellaris. 
Rhabdoceelida. 
Ruaspocara, Promesostoma solea, Macrorhynchus naegelii, M. 
croceus, M. helyolandicus, Provortex rubrobacillus. 
AtLGocaa, Plagiostoma vittatum, Vorticeros luteum, Cylindro- 
stoma inerme, 
Duke Rock. 
The Duke Rock, situated in 7 fathoms at the east entrance of the 
Sound, forms one of a number of dredging-grounds inside the Sound, 
the Turbellarian fauna of which has a common general facies. The 
conditions of life in these localities are different from those in the 
tidal zone, and the difference is expressed in the Turbellaria as well 
as in other groups of animals and plants. Thus Accela are, so far as 
my experience goes, quite unrepresented ; the Allceoceela, on the 
other hand, are abundant. 
The Turbellaria of the Duke Rock closely resemble those of the 
New Grounds, and this similarity is also borne out in the flora (see 
Johnson, ‘ Flora of Plymouth Sound,” loc. cit., p. 291). The most 
interesting form was a single specimen of Monoophorum striatum 
(Bohmig) (= Enterostoma striatum, v. Graff), which has hitherto 
only occurred at Trieste. Its carmine colour and the appearance of 
the muscles grouped in longitudinal bundles at once attract attention. 
Species of the genus Hnterostoma (perhaps at present the most 
unsatisfactory genus of all Alloeoccela) are abundant here and else- 
where in the Sound. As, however, I have not completed my revision 
of the genus, the species recorded are only part of those that were 
