154 MR. W. R. O. GRANT ON THE [Mar. 4, 



Cotylophus, Guich., in Maillard Notes sur l'lsle de la Reunion, 

 ii. Addenda C. p. 9. 



Sicydium, Sicyopterus et Microsicydium, Bleeker, Arch. Neerl. ix. 

 p. 313. 



Sicyopterus, Sicydiops et Microsicydium, Bleeker, Versl. Ak. 

 Amst. (2) ix. p. 271. 



Body subcylindrical, covered with rather small ctenoid scales ; 

 head oblong and broad, with the cleft of the mouth nearly hori- 

 zontal ; upper jaw prominent ; snout obtusely rounded ; lips very 

 thick, the lower with a series of numerous slender horizontal teeth, 

 of which sometimes only the extremities are visible. Upper jaw 

 with a single uniform series of numerous moveable small teeth at- 

 tached by ligament to the edge of the maxilla ; behind this outer 

 visible series lie numerous other parallel series of young teeth hidden 

 in the gum, which succeed the former as they become worn out or 

 broken. Lower jaw with a series of widely set conical teeth. Eyes 

 of moderate size. Two dorsal fins, the anterior with 6 (5 or 7) 

 flexible spines ; caudal quite free ; ventrals united into a short cup- 

 shaped disk. Gill-openings of moderate width ; 4 branchiostegals ; 

 no air-bladder. Pseudobranchise a slit behind the fourth gill. 



This genus, confined to fresh waters near the sea, is found 

 throughout the Torrid Zone. 



Synopsis of Species, 



I. Anterior mandibular teeth not larger than the 

 • following. 



A. Teeth in the upper jaw long, slender, and bent 



inwards at, or nearly at, right angles. 



a. Almost entirely hidden by the guvn, dorsal 



spines produced into long ribands 1. S. plumieri. 



b. Cut the gum. 



a. Maxilla does not extend to the vertical from 

 the posterior margin of the eye ; dorsal 

 spines produced into long narrow ribands 2. 8. antillarum. 



|8. Maxilla extends behind the vertical from 

 the posterior margin of the eye ; dorsal 

 spines produced into short filaments 3. S. brevifile, 



B. Teeth in the upper jaw curved, tricuspid, tri- 



dent-shaped, the middle cusp, which is sus- 

 pended at the anterior extremity of the tooth, 

 being very short, soon becomes worn away. 



a. Neck and belly naked 4. 8. gymnogaster, 



b. Neck and belly covered with small scales 5. 8. salvini. 



C. Teeth in the upper jaw curved, tricuspid, tri- 



dent-shaped, all the lobes being of nearly equal 

 length and strength. 



a. Head as broad as high; neck naked, uniform 



blackish, each scale with an oblong black 



spot. D. 6rg. A. r^ 6. 8. acutipinve. 



b. Height of the head two thirds of the width ; 



scales on the neck and belly as large as the 

 rest, uniform blackish ; caudal white-edged. 

 1 » l 



D. 6— . A.— 7. 8. laticeps 



* Specimens in which the teeth have not been examined. 



