PSYCHOLOGICAL AND ETHICAL ASPECTS. 



253 



fish present to which they may attach themselves. In fishes, it 

 must be allowed that the care, if at all evident, is usually paternal; in 

 amphibians, it is rare; in reptiles, somewhat more marked. In birds 

 and mammals, however, paternal care is general, and unquestionably 

 grows into love for offspring. 



Fig. 08. — Egg-clusters of a species of Cuttlefish — From Von Hayek. 



VI. The Habits of the Cuckoo. — As animals exhibit the 

 analogues of the human virtues, it is not surprising to find the occur- 

 rence of parallel vices. Those of much magnitude, such as paternal 

 negligence or cruelty, are however rare, for the conditions of life are 

 too simple to admit of such developed evils as in human society, 

 while the crimes of sexuality are also lessened by the limitations 

 of definite breeding-seasons. Without exposing the details of the 

 crime-list, it will be instructive, as a concrete illustration, to discuss 

 at some length the parasitic instinct of the cuckoo. 



Every schoolboy knows that the female cuckoo shirks the brood- 

 ing sacrifice usually associated with bird maternity. But though 

 as the Scriptures say, somewhat too severely, of the ostrich, "she is 

 hardened against her young ones, as though they were not hers," 

 she is not " deprived of wisdom " : by an elaborate and well-executed 

 trick she foists her several eggs, at intervals of a few days, into the 

 nests of various birds, which are usually insectivorous and suited 

 for the upbringing of the intruder. The foster-parents, all .uncon- 



