554 SMITT, ARRANGEMENT OF THE GENUS GOBIÜS. 



1: Nuraber of rays in the first dorsal fin 



6 (exceptionally 5); length of this fin, 

 from the first to the last ray (incl.) 

 less than '/g of the distance of the fin 

 from the tip of the nose. 



a: Interorbital breadth more than 10?^ 

 of the length of the head or 70 % 

 of the longitudinal diameter of the 

 eye — var. lenkoranicus (Kessl.). 



b : Interorbital breadth less than 10 % 



of the length of the head or 70 % 



of the longitudinal diameter of the 



eye — var. microps (Kr0YEr). 



2: Number of rays in the first dorsal fin 



7 or 8; length of this fin, from the 

 first to the last ray (incL) more than 

 ^^3 of the distance of the fin from the 

 tip of the nose. • — var. Ruthensparri 



(EUPHR.). 



ßßß: Number of scales in a transverse row between the 

 origins of the second dorsal and the anal fins less 

 than 8. — Gohius Jeffreysii, Gthr. 

 ßß: Cheek longer than the postorbital part of the head. — 

 Lebetus, Winther. — Gobius scorpioides, COLL, (o^ = 

 Gob. orca^ CoLL.). 

 ß: Least depth of the tail less than 7.5% of the length of the body. 

 aa: Number of scales in a transverse row between the origins 

 of the second dorsal and the anal fins less than 12. — 

 Deltentosteus, Gill. 



aaa'. Length of the ventral fin more than Y^ of the length 



of the body (without caudal fin). 



aaaa: Least depth of the tail more than 33 % of 



the distance between the origins of the first 



and the second dorsal fins. — Gob. elongatus, 



Canestr. 



