68 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 84 



than dorsal. Ventral fins small, very close together and situated 

 sHghtly behind base of pectorals. Vent preceded by longitudinal 

 striations of the skin of the belly, indicating that the region is capable 

 of some distension. Color olivaceous, fins plain, translucent, the 

 caudal dark brown. 



A single example 104 mm in standard length; taken at Chame Point, 

 Panama, by Robert Twecdlie. U.S.N.M. no. 86547 (type). 



This species is closely related to M. dipus Giinther but differs 

 greatly in the position of the vent, fin-ray, and myomeric counts. 



I take great pleasure in dedicating this species to Dr. Samuel F. 

 Hildebrand, ichthyologist. United States Bureau of Fisheries, in 

 recognition of his valuable work on the fishes of Panama. 



MICRODESMUS INTERMEDIUS Meek and Hildebrand 



Figure 12, a; Plate 2, Figure 7 



Microdesmus intermedins Meek and Hildebrand, Publ. Field Mus. Nat. Hist., 

 zool. ser., vol. 15, pt. 3, p. 957-958, fig. 2, 1928 (Panama). 



Body elongate, compressed, the caudal portion, without fin, 

 notably longer than rest of body. The body of about equal depth 

 throughout. Head 8 to 8.4 in standard length; depth 10.3 to 13.3; 

 predorsal 5.6 to 6.4; preanal 2.1 to 2.5; caudal 1.4 to 1.6; preventral 

 8 to 9.7; base of ventrals to vent 3 to 3.6. Snout 5 in head, meas- 

 ured to upper end of gill opening; interorbital 5 to 5.5. Dorsal 67, 

 anal 48, pectoral 12, ventral 1-3. Myomeres evident, 17 body and 

 34 caudal=51 muscular impressions. Vertebrae, 22 body rfhd 33 

 caudal =55. Eye minute, high, about 3 in length of snout. Mouth 

 comparatively large, the gape oblique, reaching to slightly past 

 anterior edge of orbit. Lower jaw somewhat projecting, but less so 

 than in related species, the fleshy projection at the symphysis little 

 developed; lips with, conspicuous free flanges restricted to the side of 

 the jaws and not forming a free fold anteriorly. Snout and lower jaw 

 with longitudinal grooves and ridges, the latter extending well back 

 under the branchial region. Anterior nostril in a minute pore at the 

 oral end of the frontal ridges; posterior nares in a small round opening 

 above and before eyes. Teeth small, close-set, conical, apparently in 

 two irregular series in the jaws; vomer and palatines toothless. Gill 

 openings restricted laterally, the upper end adnate to the scapular 

 region in front of the middle pectoral rays, the apertures extending 

 obliquely downward and forward to a point shghtly below the base 

 of the lower pectoral ray, the opening not quite so long as the width 

 of the fin base. Pores of the head rather smaU, five short vertical 

 rows below the eye, two horizontal rows beldnd and below eye crossed 

 by two vertical rows on the temporal region. A faint cross is formed 

 by rows of minute pores on the cheek, the juncture of wliich is about 



