DISCUSSION OF SPECIES AXD THEIR DISTRIBUTION. 393 



MACRURUS BAIRDII, Ooodi-. and Heax. (Figure 335.) 



Macnirus Bairdii, GooDE anil Bean, Amer. Jonrn. Sci. ami Arts, xiv, 1877, 471-473 (MassacliiiscHs Bay) " Cat. 

 Fish. EssexCo. and Mass. Bay, 1879,7; Bnll. Miis. Conip. Zoiil. xix, p. 195.— UoouE, I'loc. U.S.KJl'., m] 

 337, 475.— GiJNTHER, Challenger Report, xxii, 1887, 13,5, 1'l. xxxii, lisr. B. 



Body tapering- fi-om first dorsal to tip of tail, iiincli coiiipressed ])()st('riorly, its greatest 

 height over orio-iii of pectorals (O.O.'JT meter) coiitaiued 8 times iu length; its greatest width 

 at the same point (0.022 meter, contained 13 times in length. 



Scales irregnlarly polygonal, the free portions covered with transjiarent, vitreous .spines, 

 arranged in from 10 to 13 irregular longitudinal rows. On head and upi)er part of body, 

 in advance of first dorsal, the median row of spines is the mo.st prominent, and presents 

 the appearance of a low median keel. 



Lateral line nearly straight, formed by a smooth groove, which replaces two or three 

 median rows of spines of each scale. Number of scales iu lateral line, 152; 6 transverse 

 rows above it and 19 or 20 rows below it, counting from vent obliquely backward. 



Greatest length of head (0.045 meter) equals di.stance betweeu first and twenty third 

 anal rays, and is contained Gi times in extreme length. Greatest height at posterior mar- 

 gin of orbit (0.028 meter), greater than width at same point (0.023 meter), 1| times iu 

 length of head. Width of interorbital area (0.012 meter) equal to length of snout (0.013 

 meter) and length of maxillary (0.013 meter). Length of postorbital region (0.017 meter), 

 about equal to horizontal diameter of orbit (O.Olii meter). Length of operculum (0.007 

 meter) about half the length of maudible (0.015 meter). 



Snout sharp, a front view presenting four ridges radiating from the tip at right angles 

 to each other, the lower one being merely a fold in the skin of the under surfa(;e of the 

 head. The horizontal ridges are continued into the ridges upon the suborbitals, llidge 

 extending backward from tip of snout ujion top of head is lost in the interorbital space. 

 Branches of the horizontal ridges are continued upon tlie upper nuirgius of orbits, and 

 there disappear. Nostrils immediately in front of orbit, the posteiior pair much the longer. 



Mouth situated entirely on lower side of head; sj'mphysis of lower jaw iu vertical from 

 anterior margin of orbit, and articulations of mandibles in vertical from posterior margin 

 of orbit; width of cleft of mouth (0.012 meter) equal to distance between symphysis of 

 maxillaries and liueconnecting their articulations. Upper jaw protractile vertically. Barbel 

 0.005 meter iu length. 



Teeth conical, somewhat recurved, of nearly uniform size, arranged in villiform bands. 

 Palate smooth. 



Distance of first dorsal from snout (1.057 meters) about 1 times the lengtli of its base 

 (0.011 meter), and from anterior margin of orbit equal to lengtli of head. Fiist spine very 

 short (0.002 meter,) not much longer than the teeth of the second sjiine. Second si)iue in 

 length (0.032 meter) twice horizontal diameter of orbit, stout, its anterior margin armed 

 from base to tip with 15 teeth pointing upward, the uppermost slender; its length to 

 tip of filament (0.03 meter) is almost equal to distance from origin of second dorsal (0.038 

 meter), this tip when laid back reaching almost to second dorsal. Rays decreasing regu- 

 larly in length, so that, wheu the fin is upright, its shape approximates that of a right- 

 angled triangle, the hypothenuse of which is the second dorsal spine and its perpendicular 

 side a line touching the tips of the rays. 



Length of base of second dorsal (0.204 meter) less thau that of the anal, its origin 

 over tlie thirtieth scale of lateral line. Length of longest ray (in posterior third) 0.004 

 meter, which is less than length of barbel. All rays very feeble. .Meudjrane scarcely 

 perceptible. 



Distance of anal from snout (0.070 meter) 3* times iu its length of base, its origin under 

 18th scale of lateral liiie. Limgth of first ray (0.00(5 meter) one half the length of tenth 

 ray (0.012 meter), and 3 tiiuea the length of last ray (0.002 meter), the length of rays increas- 

 ing to a point beneath anterior part of first dorsal, and theuce gradual y decreasing to tip 



of tail. 



' Cat. No., U. S. National Museum, 21014, 



