1 74 Miscellaneous. 



email aquaria containing about 15 litres, the temperature of the 

 water being kept at 23°-25° C. (=73°-4-77° Y.).—Comptes Rendus, 

 December 6, 1875, p. 1136, 



Zoological Notes made during a Residence at Scheveningen. 

 By M. P. Harting. 



In these Notes we find some particulars as to the membrane of 

 the e^g of Cganca, the otoliths of Cyanea and Chrysaora, the nervous 

 system and organs of the senses of an Em-ope, and some interesting 

 researches upon the chromatophores of the embryos oiLoligo vulgaris. 

 The observations made by M. Harting upon these last organs lead 

 to some results which differ in certain points from those arrived at 

 by Harless, Briicke, and, more recently, F. Boll. 



The embryos of Loligo which furnished the Dutch naturalist with 

 the most favourable objects of study were only from 3 to 4 millims, 

 long. In living individuals of this size the body is sufficiently trans- 

 parent to allow of the employment of transmitted light, and show 

 clearly the relations of the chromatophores to the tissue surrounding 

 them. 



When the chromatophores are in a contracted state, they present 

 the appearance of small, nearly black globules, from 0-020 to 

 0*030 millim. in diameter, and consequently invisible to the naked 

 eye. They are therefore without intluence on the ground of the 

 general colour of the animal, which is milk-white. When they 

 extend, the chromatophores begin to show the colour which is proper 

 to them — that is to say, yellow, brownish or reddish yellow, and 

 more or less reddish violet ; and their transparency increases with 

 the degree of expansion at the same time that the colour becomes 

 brighter. 



M. Harting did not observe the chromatophores in course of division ; 

 he believes that the increase in the number of these organs takes 

 place by the appearance in the clear spaces of new chromatophores 

 which are at first yellow and afterwards pass to other colours. With 

 the exception of a very small number of yellow chromatophores of 

 very small size, which the author regards as being in course of 

 formation, the diameter of these organs in the expanded state varies 

 from 0-150 to 0-200 millim. ; so that they have from 7 to 10 times the 

 diameter and from 50 to 100 times the surface of the contracted 

 chromatophores. When the vitality of the animal is still great, the 

 contraction and expansion take place in a very rhythmical manner, 

 and may arrive at the number of ten to twelve changes of state per 

 minute. When life begins to fail in the embryo out of its enve- 

 lope, the movements slacken ; they afterwards cease completely ; 

 and when the animal is dead, nearly all the chromatophores remain in 

 a state of eapansion. This fact is scarcely explicable in accordance 

 with the views of those naturalists who, like Harless and Boll, 

 assume the existence of contractile fibres of muscular nature in- 

 serted in the walls of the chrnmatophorps, and producing expan- 



