62 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 84 



species. Anterior nostril in a very minute pore at the oral end of the 

 outer frontal ridge; posterior nostril close above and before e3^e. 

 Teeth very small, apparently in two irregular series in the jaws, 

 vomer and palatines toothless. Gill openings very small, oblique, 

 close in front of the lower pectoral ray, the length of the aperture equal 

 to the diameter of the pupil. Body and head, except snout and lower 

 jaw, covered with minute nonimbricate scales imbedded in the skin; 

 rows of scales of the dorsal region following the direction of the 

 myomeric impressions. Scales with 30 radiating striae. Mj^omeres 

 evident, 20 body and 23 caudal =43 muscular impressions. Ver- 

 tebrae, 20 body and 24 caudal =44. Origin of dorsal above posterior 

 third of the appressed pectoral, the fin long and moderately high, 

 attached to caudal fin at base by mem.brane; anal similar but much 

 shorter, attached to caudal by membrane. Ventrals small, close 

 together, situated directly below pectoral base. Color pale straw, 

 fins immaculate, back and sides above v/ith small dark-brown frecldes 

 evenly and uniformly distributed, lower flank and belly lighter straw. 



Five examples from Tortugas, Fla. Standard length 38.4 to 60 

 mm, of which the type, U.S.N.M. no. 102050, is the largest. Collector, 

 Dr. W. H. Longley. 



This species is distinguished from M. ionthas (Jordan and Gilbert) 

 by the smaller gill openings, number of rays in the vertical fins, and 

 proportional measurements. From M. aethiopicus (Chabanaud) it is 

 distinguished by the more anterior insertion of the dorsal fin and by 

 the much smaller gill opening. 



MICRODESMUS AETfflOPICUS (Chabanaud) 



Figure 9, d 



Leptocerdale aethiopicum Chabanaud, Bull. Mus. Hist. Nat., vol. 33, no. 3, pp. 

 230-234, 1927; Bull. Soc. Zool. France, vol. 53, pp. 279-285, figs. 1-4, 1928 

 (Cameroons) . 



Body elongate, compressed, the caudal portion without fin shorter 

 than rest of body, the vent situated about midway between the occi- 

 put and base of caudal fin. Head 10 percent of total length; depth 

 6.4; predorsal 21; preanal 54; preorbital from anterior border of eye 

 to tip of mandible 25 percent of length of head; diameter of eye 12; 

 interorbital 8; length of pectoral 50; ventral 46; caudal fin 100. The 

 diameter of the eye is contained slightly more than twice in the dis- 

 tance between the eye and the tip of the lower jaw. Tliickness of 

 the body at the base of the pectoral fins 83 percent of the depth of the 

 body at the same point; depth at base of caudal fin 41. Dorsal 47; 

 anal 26; pectoral 12; ventrals 4. Origin of the dorsal fin about one 

 head-length behind the occiput, or at a point behind the tip of the 

 snout equal to half the length of the base of the anal fin. Vertical 



