46 TURBELLARIA OF PLYMOUTH SOUND. 
hand-net among Laminaria, Oorallina, &c. A few specimens also 
occurred in tow-nettings taken close inshore and also in mid-channel, 
outside the Breakwater. At present I am unable to state whether 
these young Leptoplana belong to either or both of the species here 
recorded. The genital ducts afford the only secure diagnostic 
features, and naturally these are wanting in the present instance. 
51. LepropLANA Dr@sBacHENsIS Oersted. 
In my paper previously cited I have discussed the possible identity 
of this species with the older L. atomata, O. F. M. 
Recently, specimens from Plymouth Sound have reached me which 
agree in almost every particular with L. Drebachensis, Oe., as described 
by Jensen, and it appears probable that this species has hitherto been 
confused on our coasts with L. tremellaris, The old species, L. ato- 
mata, O. F. M., whose relations with other species of the genus are 
totally obscure, might perhaps be dropped altogether. 
B. COTYLEA. 
Family EURYLEPTIDA. 
Genus 23.—PROSTHECEREUS. 
52. ProstHEcERmus virratus (Montagu). 
This fine species, discovered by Montagu in the estuary of Kings- 
bridge, has occurred off Stoke Point on Diazona in 15 fathoms 
(Mr. Cunningham), and also in the Sound (Mr. Garstang). 
Genus 24.—CyYcLoporus. 
53. CycLoporus PAPILLosus Lang. 
Infra-littoral specimens have occurred on ascidians and sponges 
(e.g. Hymeniacidon sanguinea) dredged in the Cattewater, and also 
outside the Sound. The variety lxvigatus occurred along with 
Stylostomum variabile (to which it bears no little resemblance) in the 
river Yealm in October. The relations which appear to exist between 
this species and the substratum in which it lives are discussed by me in 
the forthcoming number of the Transactions of the Liverpool Biological 
Society. 
