450 SUMxMARY OF CURRENT RESEARCHES RELATING TO 



adornin<? the scales and fin -rays. They also occur in Cyprinodontidpe 

 and Anablepinffi. Each spinule is found to arise on or close to the edge 

 of the scale, and not on its exposed surface, like the more distinct 

 straight conic tubercles of Cyprinoids. The spinules are not always 

 perfectly straight and rigid, but may be flexible or delicate. Those on 

 the anal fin-rays are generally curved slightly, and are also often close 

 together, though not perfectly regular. They probably disappear after 

 spawning. Their arrangement or design differs characteristically in 

 different species. 



The Individual in the Animal Kingdom.* — H. V. Wilson main- 

 tains that in biology individuals concern the inquirer only in so far as 

 they are lumps of specific substances, of species-plasms. The formal or 

 morphological conception of the animal individual varies with the 

 group. An amoeba is an individual of the first order, an earthworm of 

 the second order, a " Portuguese Man-of- War " of the third order. 

 Regeneration experiments show that we cannot say of the individual, 

 " He is there, and not there," for, being " there," with a stroke of the 

 knife we can make two out of one. Phenomena of reduction or involu- 

 tion in sponges, which the author has especially studied, show that the 

 individual body may as a whole die, but remain alive in spots, the 

 flesh here passing into a condition of unspecialized regenerative tissue 

 (technically " totipotent "). Individuality is abandoned ; the constant 

 exchange of stimuh between the various parts of the body is interrupted ; 

 areas sink for the time being, at least, into a low level of non-specializa- 

 tion. Particles of fragmented sponges and hydroids may combine to 

 form the starting-point of a new creature. The uniqueness of the 

 individual must be very secondary in such cases ; the species-substance 

 is the primary and fundamental thing. This is borne out by the 

 phenomena of fusion and grafting. The individual character of the 

 organism is not radically different from that of inorganic bodies. 

 Similarly, embryos may be subdivided into two or several variable 

 embryos ; two or several may be fused ; components of two individuals 

 may be combined. The animal body is " only the expression of the 

 active forces of a specific substance, a specific protoplasm. Its uniqueness 

 in the higher forms is deceptive. The concept that an organism is 

 primarily made up of a specific plasm, and the germ-cells are only small 

 lumps of the plasm, provides in itself a sufficient working basis for many 

 classes of investigations." The author does not discuss its applicability 

 in the study of animal behaviour, where the reality of an individual agent 

 seems in many cases clear. 



Role of Selection in Evolution.f — W. E. Castle recently delivered 

 an important lecture estimating the role of selection in the light of 

 recent advances. A period of doubt was inaugurated about 1900 by 

 De Vries' Mutation Theory and by Johannsen's Pure Line Theory, and 

 many biologists regard selection as an obsolete agency. But even if 



* Journ. Elisha Mitchell Sci. Soc, xxxii. (1916) No. 4, pp. 1-18. 

 t Journ. Washington Acad. Sci., vii. (1917) pp. 369-87. 



