420 THE OPISTHOBRANCHIATB 



found no trace of it in either Scaphander, Haminea, or Philine 

 aperta. Now the two latter forms, at any rate, are largely eaten 

 by fishes/ and are inconspicuously coloured ; while Oscanius mem- 

 hranaceus is not eaten by fishes, and is handsomely coloured with 

 red-brown and yellowish markings. I am not suSiciently acquainted 

 with this animal to be able to assert anything with regard to the 

 degree of conspicuousness of these markings amid natural surround- 

 ings ; but they would appear to be conspicuous, and to assist fishes 

 in the recognition of a distasteful animal. 



6. Pleurobeanchds, Guvier. 

 7. Pleueobranchus plumula, Montagu. 



A specimen of this species was dredged in the autumn of last year, 

 south of the Mewstone, adhering to the under side of one of the 

 valves of a dead Pecten. Mr. Bourne found another specimen on 

 the shore at Wembury Bay early in May this year, and Dr. Fowler 

 brought back another from the same shore in September. 



At Falmouth, Cocks used to find it *' not uncommon" under 

 stones at Gwyllyn Vase, Swanpool, &c. 



i^aw^^i/— ETJNCINID^. 



7. RuNCiNA, Forbes, 1853 



(= Pelta, Quatrefages, 1844 j not Beck, 1838). 

 8. Rdncina coronata, Quatrefages. 



Rdncina Hancocki, Forbes. In Forbes and Hanley, Brit. Moll., iii, p. 612, 



pi. ccc, fig. 2. 



This species was first obtained at Plymouth by Mr. Heape, who 

 secured a single specimen. It was very abundant in the middle 

 of April this year in tide-pools below the bathing pond, not far 

 below high-water mark. The animals were to be seen creeping 

 over brown muddy areas and weeds, but did not frequent the green 

 weeds. The brown colour of the molluscs, although somewhat 

 deeper than that of the surfaces upon which they were crawling, 

 rendered them difiicult to detect for some little time, but when once 

 detected it was easy to find many more. When fully extended large 

 specimens measured nearly f of an inch in length. 



These pools contained, besides Runcina, large numbers of Lima- 



1 Verrill, Rep. Invert. Anim. Vineyard Sound, U.S. Fish. Rep., 1873, pp. 371, 372. 



