°%1- I Recent Literature. 1 97 



The subject of 'Protective Coloration' is discussed at considerable 

 ength, and for the most part with commendable conservatism, in compar- 

 ison with the credulous spirit in which the subject is often handled. 

 Many previously alleged cases of protective coloration are considered as 

 not proven, or as subjudtce, or as more satisfactorily explainable in other 

 ways. Furthermore, he does not consider that protective resemblances 

 between animals and their surroundings have all been produced by 

 natural selection, citing many instances in which the assimilation of 

 color to the natural surroundings is pretty obviously due to food, — as 

 notably among the various marine animals which feed upon the brightly 

 colored sea weeds among which they live. He says (p. 132) : "Consid- 

 ering the resistant nature of many pigmentary substances, vegetable as 

 well as animal, it is at least probable that a large number of cases 

 of color resemblance, often set down to the action of natural selection, 

 may be due, as in the case of Eunice, to the simple excretion by the skin 

 of these pigments which have been taken in as food. Until more is 

 known about the chemical composition of animal pigments, it -Mould be 

 rusk to adopt an elaborate explanation when the more simple one ivould 

 be sufficient." If the course recommended in the passage we have itali- 

 cised in the above quotation were generally followed in similar cases, 

 much worthless speculation would be saved, greatly to the advantage 

 of real scientific progress. Again Mr. Beddard observes: "At every 

 step, in fact, in the study of animal coloration, we are met with closed 

 doors, which can only be unlocked by keys furnished by an intimate 

 chemical and physiological knowledge such as we do not at present 

 possess" (p. 140). 



The subject of 'Warning Colors' is discussed at considerable length and 

 with great candor. Here Mr. Beddard's remark that "The field of hypo- 

 theses has no limits," and that what we need is "more study," applies 

 with special force. After reviewing the evidence, pro and con, he appears 

 to arrive at the conclusion that 'warning colors,' particularly in insects 

 and the lower forms of life generally, have not been evolved for the 

 express purpose of warning, but rather that they are concomitant with 

 inedibility — "that the brilliant colors (/. e., the abundant secretion of 

 pigment) have caused the inedibility of the species, rather than that the 

 inedibility has necessitated the production of bright color as an adver- 

 tisement" (p. 173). The theory of warning colors is, of course, that they 

 have been especially evolved to give notice of some disagreeable quality. 

 The skunk (genus Mephitis) has come to be a classic illustration of the 

 theory. But Mr. Beddard points out that in South America skunks are 

 not free from enemies, being the prey, and sometimes the chief food, of 

 many rapacious birds ; and those readers of 'The Auk' who have had much 

 acquaintance with our Great Horned Owl can give corroborative testimony 

 in respect to those of North America. 



Closely related to the theory of 'warning colors' is that of 'Protective 

 Mimicry,' to which it is supposed to furnish support. This theory origi- 



