4 AOANTIIOPTEETGII. 



Fam. 2. GOBIESOCID^. 



The Cling-fishes are small mariue fishes, easily recognizable by the naked body, the 

 short dorsal and anal fins without spinous rays, the widely separated ventral fins, which 

 are jugular in position, and by the small gill-openings. They have an adhesive ventral 

 disc, by means of which they adhere to stones or shells. They are usually found 

 between tide-marks; but Pellegrin (Bull. Mus. Paris, vii. 1901, p. 206) has recorded 

 that a species which he identifies with Goliesox adustus, Jord. & Gilb., originally 

 described from Mazatlan, is common in rapid streams near Tepic, Jalisco, and in the 

 Kio Grande de Santiaojo. 



■*&'- 



Fam. 3. GOBIID^. 



A large family, chiefly marine, but with representatives in tlie fresh waters of all 

 parts of the world. The Gobiidse may easily be distinguished from other Acantho- 

 pterygians found in the rivers of Mexico and Central America by the following 

 peculiarities : — The spinous portion of the dorsal fin is composed of a few slender 

 non-articulated rays ; the anal fim is preceded by a single slender spine ; the pectoral is 

 symmetrical and has a broad, subvertical base; the ventrals, inserted below the base of 

 the pectorals, consist each of a short feeble spine and of five branched rays ; the 

 gill-openings are restricted, the gill-membranes being more or less broadly attached to 

 the isthmus. 



Synopsis of the Genera represented in the Fresh Waters of Mexico and Central America. 



I. Ventral fins separate. 



Jaws with bands of pointed tcetli ; vomer with teeth; lower jaw pro- 

 jecting; gill-openings extending forward to below the eye . ... 1. Philypnus. 



Jaws with bands of pointed teeth; palate toothless; lower jaw pro- 

 jecting ; gill-openings not extending forward to below the eye . . 2. Eleotris. 



Jaws with bands of movable, slender teeth with trnncate apices ; palate 

 toothless; jaws equal anteriorly; gill-openings not extending 

 forward to below the eye 3. Dormitatou. 



II. Ventral fins united to form a disc. 



A. Two dorsal fins. 



1. Each jaw with a series of inimerous slender teeth, those in tlie lower 



jaw horizontal and sometimes hidden hy the gum ; lower jaw with 



an inner series of a few erect conical teeth -1. Sicydium. 



2. Jaws with bands of pointed teeth. 



Two or three fleshy flaps on the anterior edge of pectoral arch, 



projecting into the gill-cavity .5. CnoNornoRUs. 



No dermal flaps on the jjcetoral arch 6. Gobius. 



B. A single dorsal fin 7. Gobioides. 



