238 COLOUR OF CEPHALOPODA. 



strong light. I saw that the spots were very thin bodies, 

 attached to the mucous coat of the integument ; that they 

 had no connection with the epidermis ; that, in dilating, 

 their edges passed over or under each other indiscriminately; 

 that their edges were extremely sharp and well defined ; that 

 they never were increased in thickness during dilatation ; 

 and that no vessels carrying coloured fluids entered them. 

 I could not discover, indeed, any thing like either vessels or 

 nervous filaments connected with any part of the integument 

 of the animal ; and I feel assured, that, from the great size 

 of some of the spots which I had under the microscope, I 

 must have seen at least a few vessels carrying dark-coloured 

 fluids entering the mucous coat, had it been from such a 

 source that the increase in size of the spots was derived. 



" The separated piece of the mucous coat, with the palpi- 

 tating spots, remained under my microscope, exposed to a 

 strong reflected light, for three-quarters of an hour, during 

 which time I could perceive no alteration in its appearance, 

 or the strange phenomena it presented. While the motions 

 of the spots were very brisk, I suddenly removed it to a dark 

 place, where it remained fifteen minutes. On bringing it 

 again to the light, I found that all motion had ceased ; most 

 of the spots were in a state of contraction ; but, on allowing 

 it to remain for three minutes exposed to a moderately 

 strong light, the dilatations again commenced, and were car- 

 ried on unceasingly for a very considerable time. I repeated 

 these experiments with other pieces of the spotted mem- 

 brane, and always with similar results. At the end of nearly 

 two hours from the time when some of them were removed 

 from the animal, the spots were dilating ; but, in the course 

 of a few minutes afterwards, motion finally ceased." * 



4. Inky secretions. — It has been conjectured, that the 



* Edinb. Journ. Nat. and Geogr. Science, ii. 296. The paper from 

 which the above extract is taken contains the best account which has yet 

 been published of these coloured vesicles, or " chromophorous globules," as 

 they have been termed. The reader may also consult the Edinb. Phil. Journ. 

 xi. 422. The Cyprtea tigris possesses the same changeable property. 

 " Mr. Samuel Stutchbury, who had an opportunity of examining many in- 

 dividuals of C. tigris at the Pearl Islands, informed me that those cowries 

 lived there in very shallow water, and always under rolled masses of madre- 

 pore. They never were to be seen exposed to the sun's rays. On lifting 

 one of those masses, a tiger cowry was generally observed with its shell 

 entirely covered by the large mantle, which was mottled with dark colours, 

 the intensity of which the animal seemed to have the power of changing ; 

 for the colours varied in the same light and in the same medium, after the 

 manner of the spots on the cephalopodous mollusca, or, to use a more fami- 

 liar instance, somewhat in the same way that the hues of a turkey-cock's 

 wattle vary." — Bboderit in Zool. Journ. iv. 163. 



