ORGANS OF REPRODUCTION. 163 



Many Teleostei take care of their progeny, but with the 



Fig. 75. — Syngnathus acus S , with sub-caudal pouch. 



exception of Aspredo and Solenostoma, mentioned above (p 



160), it is the male on which this duty 



devolves. In some, as in Cottus, Gastrosteus, 



Cydopterus, Antennarius, Ophiocephalus, 



Callichthys, the male constructs with more 



or less skill a nest, and jealously guards 



the ova deposited in it by the female. 



The male of some species of Arius carries 



the ova (Fig. 7l) about with him in his 



capacious pharynx. The species of Chromis, 



inhabiting the sea of Galilee, are said to 



take care of their ova in the same manner. 



And, finally, in the Lophobranchs, nature 



has aided this instinct by the development 



of a pouch on the abdomen or lower side 



of the tail. In the Syngnathidae this pouch 



is formed by a fold of the skin developed 



from each side of the trunk and tail, the 



free margins of the fold being firmly united 



in the median line, whilst the eggs are 



being hatched in the inside of the pouch. 



In Hippocampus the pouch is completely 



closed, with a narrow anterior opening. 



The genital organs of Ganoids show 

 similar diversity of structure as those of 

 Teleosteans, but on the whole they approach 



Fig. 76.— Sub-caudal 

 pouch of Sjmgnathus 

 acus, with the young, 

 ready to leave the 

 pouch. One side of 

 the membrane of the 

 pouch is pushed 

 aside to admit of a 

 view of its interior. 

 (Natural size.) 



