LOCATION OF THE SACCVLUS IN FISHES. 143 



thin bone jutting out to the right and left of the basi-occiput 

 give the location of the sacculi, the sagitta showing through. 

 The sacculus is in a pocket open at the top, through which it 

 could be lifted out without cutting. The sagitta is of fair size. 



URANOSCOPIDiE. 



The site of the sacculus in Uranoscopus scaber, a Mediterra- 

 nean fish, is shown by a large swelling externally. The sacculus 

 lies in an open depression, the lagena end extending into a 

 pocket of its own. 



Callionymidje. 

 In Callionymus lyra (the " Skulpin ") the sacculus lies openly 

 on the floor of the cranial cavity ; no special depression exists 

 for it. 



Blenniid^e. 



There is no external evidence of the situation of the otoliths 

 in Anarrhichas lupus, the largest British representative of this 

 family, and known to fishermen as the " Cat Fish." The sacculus 

 lies in a shallow open depression : the whole sacculus was lifted 

 out without difficulty. It was the same in a specimen of Blennius 

 ocellaris (the " Butterfly Blenny "). The sagittse in this family 



are small. 



Batrachid^. 



The Basi-occiput in Batrachus surinamensis (the " Pacuma " 

 of Demerara) shows a large bulbous swelling under the site of 

 the sacculus quite incommensurate with the size of the sagitta 

 when this is got out. The sacculus lies in an open depression ; 

 the lagena is attached not at the extremity of the sacculus, but 

 placed about a quarter of the length of the sacculus from the 

 posterior end. 



ZoARCIDiE. 



The sacculus lies in an open cavity, from which it could be 

 picked out entire in Zoarces viviparus (the "Eel Pout"). 



OPHIIDIID.E. 



The bone of Ophidium barbatum is very thin where it lies 

 under the sagittse, which are plainly visible through it ; they are 

 large and solid. The angle they make with the middle line of 

 the skull is very distinct. 



