104 THE ZOOLOGIST. 



the divergence of the sagittae. This is seen in Antennarius 

 hispidus, a small-sized member of the Angler family from the 

 Indian Ocean ; in Ophiocephalus punctatus ; and markedly so in 

 Anabas scandens (the Climbing Perch of India), where the bony 

 excrescences look like the buds on opposite sides of a twig just 

 before they burst open. When the skull is opened by a vertical 

 cut down the middle, the differences in the location of the 

 sacculus can more readily be appreciated. In some fishes this 

 lies nearer the eye orbit, in others it is further away. Again, 

 in some it is close to the middle line of the head, in others it is 

 away to the side of the skull ; this is noticeable in the Gobiidce 

 (the Gobies) ; in Tetrodon leopardus (an Indian Globefish) ; and 

 in Anableps tetropthalmus (the Four Eyes of Demerara). In the 

 Mormyridce (Nilotic fishes) quite a different arrangement to the 

 usual one is to be seen. The sacculus is attached in Mormyrus 

 kannume to a bladder-like termination of the swimming bladder, 

 and is situated at the back part of the skull. In some families 

 the 6acculus is completely embedded in the basi-occiput bone, 

 which has to be carefully split up to extract the sacculus and its 

 contents. This is so in the Characinida, the Cyprinidce (the 

 Carps), and the Silurida (the Cat fishes) ; all belonging to the 

 Ostariophysi suborder of fishes, i. e. those that have their 

 swimming bladder connected with their hearing organs by 

 means of a series of bony ossicles known as the " Weberian 

 ossicles." In other fishes the sacculus with its enclosed otoliths, 

 although embedded in a bony pocket, is not so solidly encased 

 as in the Ostariophysi, and the opening where the junction of the 

 sacculus with the utriculus is effected is more patent. In some 

 this opening is small and the bony walls of the pocket have to 

 be cut away to release the sacculus ; in others the opening is 

 big enough to allow the sacculus to be lifted out through it. 

 Other fishes have the sacculus lying fairly open in a depression 

 rather than a pocket, whence it can be lifted out with a pair of 

 forceps and removed, a trifle of bone perhaps having to be cut 

 away to release one or other end of the stone ; this is so with 

 Gadus merlangus (the Whiting). Again, the sacculus may be 

 lying in the open on the floor of the brain cavity, it can be 

 picked up and removed without further trouble ; this is so with 

 Zeus faber (the John Dory), and Batrachus surinamensis (the 



