2784 Bulletin 4.7, United States National Museum. 



200. TACHYSURUS MELANOPUS (Giinther). 



D. I, 7; A. 21; P. I, 10. The height of the body is contained 5 times in 

 the total length (without caudal), the length of the head 4fc times; head 

 somewhat broader than high, its greatest width being f of its length ; the 

 occiput and nape are finely granulated ; occipital process subtriangular, 

 as long as broad, with the lateral margins somewhat concave, and with 

 the median ridge a little elevated. The longitudinal groove in the mid- 

 dle of the crown of the head is indistinct, narrow, linear behind, scarcely 

 extending to the base of the occipital process. The teeth on the palatines 

 are obtusely conical, and form 2 rather small subovate patches, apart 

 from each other, and situated 011 the front part of the palate. The max- 

 illary barbels do not quite extend to the middle of the pectoral iin. Dor- 

 sal spine of moderate strength, scarcely serrated anteriorly, equal in 

 length to the distance of the gill opening from the anterior margin of the 

 orbit, or even somewhat shorter; adipose iin small, the length of its base 

 being less than that of the dorsal; pectoral spine nearly as long and 

 strong as that of the dorsal fin, very strongly serrated anteriorly. Porous 

 axillaries nearly as wide as a nasal opening. The upper (inner) surface 

 of the ventral iins deep black, the lower (outer) white; the inner sur- 

 face of the pectorals blackish. Rio Motagua (east slope), a-b. From 8 

 to 9 inches long. From Mr. Salviu's collection. (Giiuther, Cat., V, 172.) 

 The specimens from the Pacific Coast mentioned in the text (page 132) 

 belong to the following species. 



200(a). TACHYSURUS LIROPUS, Susan B.Bristol. 



Head 3f to 3f; depth 4 to 5^. D. I, 6; A. II, 19; P. I, 9 or 10. Body 

 elongate, its width anteriorally a little less than depth, the posterior 

 portion much compressed ; back elevated at front of dorsal ; anterior pro- 

 file from front of dorsal to tip of snout oblique ; head flat, very broad, 

 its width \\ in its length ; snout broad, rounded, 1^ ibo \\ in interorbital 

 width ; eye rather large, laterally placed, its width about If in its length, 

 44 to 4j 2 o in head; mouth small, upper jaw considerably projecting, its 

 breadth 2f to 3 in head; jaws thin; wide bauds of minute pointed teeth 

 present on both jaws; vomerine bands widely separated, and indistin- 

 guishable from the palatine band, which is small, oblong-ovate, and 

 scarcely prolonged backward ; interval separating vomerine bands about 

 2 or 3 in eye; the teeth on these bands larger than those on jaws, and 

 very bluntly conical. Interorbital space broad, 2 to 3 in head. Barbels 

 long and slender, the maxillary barbel extending to, nearly to, or, in 

 some cases, past base of pectoral, 1 ^ to If in head ; outer mental barbel 

 1^ to If in head; inner mental barbel 2 to 2| in head. Antedorsal 

 shield very short, narrowly crescent-shaped, its length on the median line 

 about 2 or 3 in its width; occipital process sub triangular, a little longer 

 than broad at base, its edge slightly concave, its median keel strong. 

 The long, narrow groove of the fontanel beginning abruptly a short dis- 

 tance in front of occipital keel, the distance from its end to base of dorsal 

 Ig to 2 in the distance to tip of snout. Shields of head rather smooth, 

 finely granular, the granules forming distinct lines anteriorly. The flat 



