Manchester Me7Hoirs, Vol. xlviii. (1904), No. VS. 



XV. Notes on some Polyclad Turbellaria in the 

 British Museum 



By F. F. Laidlaw, B.A. (Cantab.) 



/ 



Received and Read March 2gth, igo4. 



PLANOCERIDy5i. 



Planocera pelagica (Moseley). 



Styloc/nis pelagzcHs, Moseley ['77]- 



Planocera pelagica, Lang ['84]. 



Stylochoplana sargassicola, von Graff ['92] (partim). 



Three specimens, collected " from February 28th to 

 March 5th, 1889. Surface of N. and S. Atlantic, and 

 from Cape [of Good Hope ? ] to Australia. Capt. 

 Carvasso." 



This is the smallest species of the genus with the 

 exception of PL simrothi which is of about the same size 

 with it. There can be no doubt that this species is a true 

 Planocera closely allied to PI. pellucida but distinctly 

 smaller and with differently arranged eye-spots. 



The length of the three specimens in the collection 

 ranges from 8 to 10 mm. and the breadth from 5 to 7 mm. 

 In Moseley's figure ii ['77, Z-^- HI.] MG is really, I think, 

 the female opening whilst FG is the opening of the non- 

 muscular part of the vagina into the muscular part or 

 bursa copulatrix. 



The species is quite distinct from Stylochoplana 

 sargassicola. (Mertens) 



It would be interesting to compare its distribution 

 with that of Planocera pellucida. The latter appears to 

 have a very wide range, whilst P. pelagica is perhaps 

 confined to the Atlantic. 



