REPRODUCTION AND SEX 561 



fondness; psychical chains have been forged which bind the mates 

 together as willing captives to one another. The beating heart of 

 monogamy is the love of mates. So in these times, when our tradi- 

 tional human pairings are being so widely criticised, and even so 

 boldly relaxed, must not the evolutionary naturalist put in the 

 warning word — beware of reversions ! 



Male Parents Mothering the Offspring. — At various levels 

 among animals the parental care has become altogether paternal. 

 This is true of a few birds like the American Ostrich or Rhea, where 

 the male does all the brooding and afterwards leads the young ones 

 about. In the Grey Phalarope, that nests in Greenland and Iceland, 

 the more brightly coloured female does all the courting and the 

 male does most of the brooding; in the Red-necked Phalarope, that 

 nests as far south as the Orkneys and Shetlands, the female again 

 does most of the courting and the male most of the brooding and 

 nurture. The exceptional exchange of roles is completed when the 

 female mounts guard over the brooding male ! 



It is the male stickleback who builds the nest, binding the parts 

 together with threads exuded from his kidneys. The little polygynist 

 brings the nonchalant females to his neat construction, in which 

 each lays a few eggs and departs, careless of either conjugal or 

 parental responsibilities. Then he mounts guard over the fertilised 

 eggs, driving away enemies, eating nothing all the time. When the 

 eggs hatch and the living marks of interrogation come out, he still 

 watches over them, trying to keep them within bounds. The male 

 stickleback is a motherly father ! 



The quaint nurse-toads or obstetric toads of the Continent pair 

 on land, not, like ordinary frogs, in water. The female liberates a 

 string of 18-38 eggs, and the male gets this attached to his hind legs. 

 For a time he keeps in private life, hiding himself in a damp hole. 

 Occasionally he ventures into a pool for a bathe. The eggs go on 

 developing, still attached to his legs. Tadpoles are formed within the 

 egg-membrane, and there they pass through the stage with the 

 first or external set of gills. When they reach the stage with the 

 second or internal set of gills, the father-toad jumps into the water. 

 Then the egg-membranes are burst, and the tadpoles swim away. 

 The male is freed from his living shackles, and not very unlike 

 shackles they are. He creeps on to land again, and long afterwards 

 his family do the same. For the period of infancy this nurse-toad is 

 a motherly father ! 



One would like to have a more intimate knowledge of the strange 

 animals called sea-spiders or Pycnogons, which are represented by 

 many kinds, from the shore to the great depths. For the eggs 

 liberated by the female are carried by the male, attached in two 

 bunches to the third pair of appendages. The corresponding limbs 



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