1903. ] POLYCLADS OF THE ‘‘ SKEAT EXPEDITION.” 303 
Mr. Evans on the shores of the island of Pulau Bidan, where it is 
evidently one of the commoner species. 
The body of this worm is rather elongated, rounded in front 
and with a pointed hinder extremity. The arrangement of its 
eye-spots is shown in the accompanying figure (text-fig. 50). 
Text-fig. 50. 
€ . s ee 
aiiey CG) oa 
. e « ote 5 
ere, 2° . 
© wena 
« « e +A 
e 
* e “6 oe o @e 
€ ee » © @ “s 
e « ® 
° ° 
Cyt © 
e « e i 
« e 
e e 
Eye-spots of Notoplana evansii. 
Unfortunately I have no notes as to colour, but, judging from the 
spirit-specimens, the creature is probably of a yellowish-grey 
colour, with a small number of irregularly scattered black spots. 
The gut-branches are numerous, and there is no anastomosis. 
The dimensions of an average individual are as follows :— 
Iya t Ae edbacoucon an ohenonemarn ac ghas do 25 mm. 
BCG 2 retrace tite. sectors stelatstteioe cielo gee Laat, 
Tentacles from ant. margin............ ens; 
Mouth-opening ok ne weno. EP ak}, 
d. Aperture behind mouth ......... BD) 45 
Oe - behind male ............ TED: 555 
Genital Apparatus (see text-fig. 51, 304). 
The most striking features of the male copulatory apparatus 
ave the great length of the antral chamber and the chambered 
prostate organ, the latter recalling the prostate of certain 
Leptoplanas, e. g. Z. aleinoi. From the male aperture the antral 
cavity (text-fig. 51, a.m.) extends forwards as far as the level of the 
hinder end of the pharynx. It has very muscular walls and runs 
sloping in an upward direction. Lang, in his diagram of the 
genital apparatus of Hoploplana (Planocera insignis group [6}), 
calls this chamber the penis-sheath (‘‘ Penisscheide), but this term 
should, I think, be reserved for the sheath-like folds of the walls 
of the antral chamber occurring in Cestoplana and in certain 
Cotylean genera. 
The lining of the walls of the antral chamber in the present 
species consists of a flattened ciliated (?) epithelium ; the muscular 
wall consists of a thick layer of interlacing circular fibres. 
Proc. Zoou. Soc.—1893, Vor. I. No. XX. 20 
