the Development of Anableps Gronovii, 433 



one forms a nest upon the bottom with pieces of grass and 

 other vegetable substances, which are woven together, form- 

 ing a covered structure, with two openings, so that when the 

 fish enters it can pass through without being required to turn 

 round to come out. If the materials prove too light, and show 

 a tendency to float, they are loaded with stones till the nest 

 is securely anchored.* 



The other species constructs its abode upon some aquatic 

 plant elevated above the bottom, or upon some submerged 

 branch or twig of a tree. During incubation, the ova are 

 guarded by the male, and protected against the depredations 

 of the females, which are always ready to devour the eggs 

 almost as soon as deposited.! 



In another group of fishes, the eggs are neither scattered 

 upon the bottom nor deposited in nests, but assume a more 

 intimate relation with the parent, though still conforming to 

 the oviparous mode. In the Pipe fishes they are attached to 

 the body of one of the parents. In one species, Syngnathus 

 ophiodon, the eggs merely adhere to the under side of the 

 abdomen of the male, where they remain till hatched. But 

 in S. acus, as observed by Ekstroem and others, and in S. 

 Peckii, as observed by Storer and myself, there is found a true 

 marsupial pouch, consisting of two folds of skin, posterior to 

 the anal opening of the male. These folds are directed in- 

 wards, and meet on the median line. In this pouch the eggs 

 are deposited by the female, and remain there till incubation 

 is complete, and even after the eggs are hatched the young 

 return to the pouch as a place of refuge. 



In all of the preceding instances the foetus is developed 

 exterior to or upon the surface of the body. The Pipe-fishes, 

 which are analogous to the Marsupials among Mammals, form 



* For a very interesting account of the nest-building of the Sticklebacks, see 

 Hancock Ann. & Mag. of Nat. Hist. Vol. X. N. S. p. 241. 



1 1 have witnessed, this habit in a pregnant female which was in my posses- 

 sion. The eggs were deposited during the night, but on the following morning 

 nothing remained of their contents, the empty envelopes being scattered about 

 the bottom of the vessel. 



JOURNAL B. S. N. H. 56 NOVEMBER, 1854. 



