546 SMITT, ARRANGEMENT OF THE GENUS GOBIUS. 



aaa: Least depth of the tail less than 32 % of the length of 

 the head. 



aaaa: Length of tlie base of the anal fin less than 90 % 

 of the length of the head. — Gohius batrachoce- 

 plialus, Pall. 



aaaaa: Number of scales in a transverse line at the 

 beginning of the second dorsal fin more than 

 23, in a longitudinal line, above the före part 

 of the anal fin, as long as the lower jaw, 

 more than 16; length of the head reduced 

 more than \/^ of the length of the body 

 (without caudal fin); the whole opercle in 

 adult State usually naked. — forma hatra- 

 chocephalus. 

 ßßßßß: Number of scales in the above-naraed trans- 

 verse line at most 23, in the longitudinal line 

 of the above-naraed length at most 16; length 

 of the head reduced less than 24 % of the 

 length of body; upper part of opercle scaly. 

 — forma platycephalus, Kessl. {= Kessleri, 

 Gthr.) + eur^stomus, Kessl. 

 ßßßß- Length of the base of the anal fin more than 90 % 

 of the length of the head. — Gobius ßuviatilis, Pall. 

 aaaaa: Length of the base of the second dorsal fin 

 more than 38 % of the length of the body 

 (without caudal fin) — forma cepypterus 

 (Kessl.). 

 ßßßßß: Length of the base of the second dorsal fin 

 less than 38 % of the length of the body. — 

 forma. ßuvmtilis, incl. Gobius gymnotrachelus, 

 Kessl. 

 ßßß: Least depth of the tail more than 32 % of the length of 

 the head. 



aaaa: Least depth of the tail less than 32 ?^ of the length 

 of the base of the second dorsal fin, which is more 



