442 TUB OPISTHOBRANCHIATE 



not elong'afce and narrow as usually iu F. coronata ; its anterior 

 angles were produced into long processes. The oral tentacles were 

 very long and slender^ rather over ^ inch in length (cf. A. and H. 

 on this character in young specimens of F. Drummondii). Bkino- 

 phores perfoliate, with numerous laminae alternately larger and 

 smaller, resembling those described and figured 'by Alder and Han- 

 cock for F. Drummondii much more than for F. coronata (where 

 they are less numerous). When contracted the rhinophores appeared 

 to be annulate, not perfoliate. Cerata very numerous, clustered, 

 the first cluster being very large ; very contractile and changeable 

 in shape, capable of much elongation. Colour of body transparent 

 white, with patches of opalescent blue spots on the head, back, 

 alonar the oral tentacles, and on the anterior faces of a few of the 

 larger cerata. Hepatic cfeca granular, yellowish brown ; no pink 

 or red at all in this specimen. Crescentic patches of opaque white 

 on the anterior faces of the tips of the cerata. 



In all points of external form and in the colour of the hepatic 

 cgeca this specimen agrees much more with the descriptions of F. 

 Drummondii than with those of F. coronata, but on account of its 

 possessing the opalescent blue markings, characteristic of the latter 

 species, and not known to occur in the former, I have referred it with 

 some hesitation to the species corona.ta. The specimen described 

 in my former Report under the provisional name of Folis Huxleyi 

 (1. c, pp. 194, 195) I am inclined now to regard as a young Face- 

 Una coronata, in which some of the cerata had been broken off ante- 

 riorly. In very many points it agrees perfectly with the young 

 individual just described. 



The long oral tentacles of F. coronata are naturally employed very 

 differently from the short tentacles of Galvina tricolor ; they are not 

 kept motionless and flat in locomotion, but are swayed about, feeling 

 the surface and the surrounding medium on all sides. It may be 

 noticed in Solids that the oral tentacles are as a rule particularly 

 long where the dorsal tentacles are laminated or otherwise dis- 

 tinctively specialised for olfactory purposes. This increased develop- 

 ment of the oral tentacles probably saves the rhinophores from many 

 liabilities to danger. That this view of the correlation is not merely 

 fanciful is borne out by the condition of the same parts in the Holo- 

 hepatica, where the rhinophores are protected either by being re- 

 tractile into sheaths {Dorididse cryptohranchiatas), provided with 

 special tactile appendages [Ancula cristata, Idalia), correlated with 

 special development for tactile purposes of the oral tentacles {Gonio- 

 doris) or anterior extensions of the pleuropodia [Triopa claviger, Poly- 

 cera), or by having the laminated portion bent backwards {Acantho- 

 doris pilosa, Polycera) . When a Facelina coronata also is at rest 



