102 Mr. Patterson on the Cydippe Pomiformis. 



with their companions, without their having received any apparent injury. If 

 the finger be pressed against one recently dead, the Beroe will not, by such a 

 pressure, be changed into a broken and shapeless mass. It will, on the contraiy, 

 by its smoothness and elasticity, slide from beneath the finger. In this respect it 

 formeda singular contrast to the Bolina Hibernica, which could scarcely be removed 

 without injury, and when taken in the hand appeared a shapeless mass of jelly. 

 Some of the continental writers do not appear to have noticed this difference in 

 the consistency of different Beroes, and have applied to the entire family, obser- 

 vations which are only correct when applied to particular species. Thus Lesson 

 describes them as " peu consistant se brisant aisement a la moindre pression ;"* 

 and Blainville, under the genus Cydippe, introduces the observation of Othon 

 Fabricius : " C'est un des plus jolis animaux qu'il soit possible de voir ; mais 

 aussi I'un des moins consistance, car a peine est il touche, qu'il est brise et reduit 

 en morceaux."f 



From the inconsiderable quantity of solid material which enters into the body 

 of the Beroes, and the rapid circulation of water, which is apparent throughout 

 their frame, we would naturally suppose that any tinge which the body might 

 accidentally acquire would be extremely fugitive. It was found, however, to be 

 much less so than a priori would have been expected. My attention was drawn 

 to this peculiarity by the circumstance of all my glass vessels being one evening 

 occupied by Beroes and Crustacea, so as to compel me to place a small Medusa 

 in a tin vessel, which chanced to be rusted at the seams. Next morning the 

 colourless appearance of the animal was changed to a bright yellow, which 

 appeared to pervade every part, and doubtless arose from the oxide of iron dif- 

 fused through the sea water. This tint remained during the entire day, although 

 the animal was transferred to pure sea water. Wishing to try if the vessels of 

 the Beroe would become distinct, if filled with some coloured fluid, from which 

 the animal could suddenly be withdrawn, and viewed through the usual transpa- 

 rent medium of sea water, I placed a Beroe in a weak infusion of saffron. At 

 the end of twenty minutes its colour had undergone a perceptible change. I 

 allowed it, however, to remain immersed for about six or seven hours, when it 

 had assumed a bright yellow hue. It was then placed in pure sea water, but 



* Annates des Sciences, tome v. p. 236. ■)■ Manuel, p. 151. 



