1508 BitUctin //, United States N'ational Museum. 



scale, like flakes of snow, regularly arranged in small number, some 20 on 

 each side above the 1>ody, a few on the median fins. Seen once at Havana. 

 (Poey.) Length 2 inches. A doubtful species, apparently referable to 

 MicrosjMthodon, possibly the young of M. chrysurus. {niveatus, snowy.) 



Pomacentrtts niveatus, Poey, Enumeratio, 102, 1875, Havana. 



1982. MICROSPATHODON DORSALIS (Gill). 



Head 3J; depth 2 in length to tip of caudal rays; eye small, high, 2^ in 

 preorbital width, 5 in head. D. XII, 16; A. II, 14; scales 29, with 22 

 pores. Body deep, compressed, the nape high and compressed, the ante- 

 rior profile very steep, slightly concave in front of orbits. Head very 

 wide and heavy below, mouth wide, transverse, its width nearly twice its 

 lateral cleft, the maxillary reaching vertical from midway between nostril 

 and front of eye. Maxillary almost wholly slipping under the broad pre- 

 orbital, its distal half strongly U-shaped, with the convexity backAvard, 

 and its anterior margin displaying a deep reentrant curve. Dentary por- 

 tion of mandible consisting of an anterior transverse portion, and the 2 

 lateral limbs, which form about aright angle with anterior portion, and are 

 convexly bent toward median line. It would much resemlile a U with the 

 lateral limbs convex inward instead of outward; anterior portion pro- 

 vided with a single series of rather firmly fixed elongate incisor teeth 

 with truncate edges; lateral teeth similar but smaller; teeth in the upper 

 jaw strongly compressed laterally, but with the exti'eme tip flattened 

 autero-posteriorly, so as to render them narrow incisor-like; very loosely 

 implanted, extremely movable, and in a single functional series, the teeth 

 of which are replaced by others which appear above along front of jaw; 

 between vomer and front of jaw is a median firm fleshy pad, with free 

 anterior margins; a somewhat similar pad at each angle of mouth; no 

 teeth on vomer or palatines. Nostril minute, round, midway Itetween front 

 of jaw and middle of orbit. Preopercle smooth or minutely creuate at 

 the angle, none of the l)ones of head serrate or spinous. Gills 3i, the inner 

 half of fourth gill developed about I length of others; a small l)ut evident 

 pore behind fourth gill; gill rakers short and weak, not toothed, about 

 20 on anterior limb of outer arch; gill membranes forming a broad fold 

 across the isthmus. Scales large, rough, vertically much deeper than 

 wide, with numerous small accessory scales at base which l)ocome exceed- 

 ingly numerous on head and nape, where they form a shagreen-like cover- 

 ing; lateral line little prominent, the pores opening on under surface of 

 scales, ceasing under last rays of soft dorsal. Fins entirely enveloped in 

 scales, which are large at base of fins, becoming minute on soft portions. 

 Dorsal spines strong, regulai-ly increasing, the highest 2i in head; anal 

 spines strong, the second but little shorter than hmgest dorsal spines; 

 soft dorsal and anal fins conspicuously falcate, the median rays of fins 

 produced beyond fork of caudal, the anterior margins stongly convex, the 

 ]>o8terior strongly concave; longest dorsal and anal rays more than ^ 

 length; caudal deepljMbrked, the lobes also greatly falcate, equaling in 

 length the lobes of dorsal and anal; outer ventral rays produced, extend- 



