464 THE ZOOLOGIST. 



fetched this comparision between the two localities may seem at 

 first sight, everyone who has had an opportunity of thoroughly 

 observing the characteristic forms of vegetable and animal life in 

 woods, and at the bottom of the sea, will inevitably be convinced 

 of its accuracy.* Again, in primitive plant life (Thallophyta), in 

 the family Caulerpacece, "the genus Caulerpa contains nearly one 

 hundred species, which present the most varied external forms, 

 simulating those of many of the higher plants, such as Mosses, 

 Ferns, Mare's-tails, Cactuses, Conifers, &c." f It has been sug- 

 gested that some of the seeds of Ewphorbiacece, notably those of 

 the Castor-oil plant (Ricinus), resemble beetles, and, as such, 

 may be mistaken by birds and carried a small distance before 

 being dropped. This seems very doubtful. Ricinus seeds and 

 those of Para Rubber (Hevea braziliensis) , which resemble them 

 on a large scale, are ejected explosively from their capsules to a 

 distance quite sufficient for their dispersal, and falling, as they 

 constantly do, among the herbage, would certainly escape most 

 insect-eating birds. I 



Fishes of the family Pomacentridce, belonging to the spiny- 

 finned division, which frequent the neighbourhood of coral reefs 

 and islands, and thus closely resemble the scaly-finned fishes, 

 Chsetodonts, in their mode of life, also are very similarly and 

 beautifully coloured. But in the opinion of Dr. Giinther this is 

 one of many instances showing that the colouration is due to a 

 great extent to " the agencies of climate, of the surroundings, 

 and of the habits of animals." § 



Active Mimicry. 

 Another and very important distinction to be drawn when 

 dealing with instances of mimicry and protective resemblance is 

 one long since pointed out by Kirby and Spence, and one that 

 demands the utmost consideration. To use the words of the 

 teleological authors of the immortal ' Introduction to Entomology,' 

 there are Passive means of defence, such as are independent of 

 any efforts of the insect; and Active means of defence, such as 



* Kerner and Oliver, ' Nat. Hist. Plants,' vol. i. p. 112. 



f Ibid. vol. ii. p. 645. 



I H. M. Eidley, ' Nat. Science,' vol. viii. p. 196. 



§ ' Introd. Study Fishes,' p. 524. 



