BLENNIES. 



393 

 In the other 



figured species (Chirus hexagrammus) being from Japanese waters. 



genera the lateral line is single. 



The fourth family of the group (Blenniidce) is much more 

 Blennies. J & r \ _ 



extensive than either of the others, comprising a considerable 



number of genera, some of which are rich in species. The family agrees with the 



hairy-backs in the jugular position of the pelvic fins, which, when present at all, 



are composed of a very few soft rays. In the anal fin, the spines are few or 



wanting, and there is very generally a papilla in the neighbourhood of the vent. 



The low and elongate body is more or less cylindrical in form, and either naked or 



covered with scales, which are generally of small size. The dorsal fin, which may 



be either single, double, or triple, occupies nearly the whole length of the back ; 



and when it has a distinct spinous portion, this is at least as much developed as the 



soft part, while in some instances the whole fin may be spiny, the anal being 



JAPANESE CHIRUS. 



elongate. In most cases false gills are present. All the marine members of the 

 family are littoral forms, and the majority are of small size, while some are among 

 the smallest of all fishes. They are abundant throughout all tropical and temperate 

 seas: and whereas some forms inhabit brackish water, others are exclusively fresh- 

 water. Dr. Giinther writes that "one of the principal characteristics of the 

 blennies is the ventral [pelvic] fin, which is formed by less than five rays, and has 

 a jugular position. The blennies have this in common with many gadoids [cod 

 tribe], and it is sometimes difficult to decide to which of these two families a tisli 

 should be referred. In such doubtful cases the presence of the pseudobranchia 

 (which are absent in gadoids) may be of assistance. In many blennies the ventral 

 fins have ceased to have any function, and become rudimentary, or even entirely 

 absent. In others, the ventral fins, although reduced to cylindrical stylets, possess 

 a distinct function, and are used as organs of locomotion, by the aid oi which the 

 fish moves over the bottom." The family is not definitely known in a fossil state 

 although it may be represented by an extinct genus in the Monte Bolca Eocene. 



