436 THE OPISTHOBRANCHIATB 



Cratena viriJis. In contrasting Eolis northumhrica with Eolis 

 viridis, Alder and Hancock entirely overlooked the fact that in 

 Forbes's original specimen of the latter species the rhinophores were 

 described as being " rugose^ or wrinkled concentrically." It is a 

 very common occurrence for an -^olid possessing " smooth " rhino- 

 phores to contract them so as to give them the appearance of being 

 " ringed " or annulate in structure ; and I cannot help regarding the 

 appearance described in Eolis northumhrica as being probably a 

 transient, and not a specific difference. 



Cratena viridis has been found in greatest abundance at St. 

 Andrews by Prof. Mcintosh/ who notices how readily this species 

 loses its characteristic coloration in captivity. I can confirm 

 Prof. Mcintosh's statement by my observations on our Plymouth 

 specimens. 



25. ^Cratena olivacea^ A. and H. (= Gavolina oUvacea of 1st Rep., 



p. 183). 



This species has not again been obtained. 



Sub-family 3. — Tergipbdin^. 

 20. Tergipes, Guvier. 



26. ■'^Tergipes despectus, Johnston. 



This species has not been noticed since my former Eeport. 



21. Galvina, Aid. and Hanc. 



27. GrALViNA EXiGUA, A. and H. 



This species has been taken on two occasions. One specimen was 

 found among Halecium and Eudendrium on stones dredged near the 

 Duke Rock, March 27th, 1890. It possessed five rows of cerata, 

 the first half-row consisting of three cerata, the middle half-rows of 

 two, and the posterior of one. The dorsal tentacles were twice as 

 long as the oral. The cerata and tentacles were banded trans- 

 versely with belts of olive-green, and there were reticular patches 

 of the same pigment upon the dorsal integument. 



Another specimen, quite colourless, was taken on Halecium 

 dredged near the same spot on April 9th. It was some time before 

 this individual was noticed, owing to the perfect resemblance of its 

 cerata in form and colour to the white elongate gonophores of the 

 Hydroid. 



^ Loc. cit., p. 5. 



