DISCUSSION OF SPECIES AND THEIR DISTRIBUTION. 393 



MACRURUS BAIRDII, Goode and Bean. (Figure335.) 



Mm in r us Bairdii, Goode and Bean, Amor. Joum. Sci. and Arts, xiv, 1877, 471-473 (Massachusetts Baj i; Cat. 



Fish. Essex ('■>. and .Mass. Bay, 1879, 7; Ball. Mas. C p. Zoiil. six, p. 195. — Goode, 1'roc. U.S.N. M., in, 



:s:'.7. 175.— <:i niiii:i:. Challenger Report, x\n, 1887, 135, PI. xxxn, fig. B. 



Body tapering from first dorsal to tip of tail, much compressed posteriorly, its greatest 

 lieighl over origin of pectorals (0.037 meter) contained 8 times in length; its greatest width 

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



Scales irregularly polygonal, the free portions covered with transparent, vitreous spines, 

 arranged in from 10 to 12 irregular longitudinal rows. On head and upper part ofbody, 

 in advance of first dorsal, the median row of spines is the most prominent, and presents 

 the appearance of a low median keel. 



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

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

 rows above it and 10 or 20 rows below it, counting from vent obliquely backward. 



Greatest length of head (0.045 meter) equals distance between 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 thau width at same, point (0.023 meter), If times in 

 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 (0.010 meter). Length of operculum (0.007 

 meter) about half the length of mandible (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 surface of the 

 head. The horizontal ridges are continued into the ridges upon the suborbitals. Ridge 

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

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

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



Mouth situated entirely on lower side of head; symphysis of lower jaw in 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 line connecting their articulations. Upperjaw protractile vertically. Barbel 

 0.005 meter in 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 4 times the length of its base 

 (0.014 meter), and from anterior margin of orbit equal to length of head. First spine very 

 short (0.002 meter,) not much longer than the teeth of the second spine. Second spine 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. Hays decreasing regu- 

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

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

 side a line touching the tips of t he rays. 



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

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

 meter, which is less than length of barbel. Ail rays very feeble. .Membrane scarcely 

 perceptible. 



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

 ISth scale of lateral line. Length of first ray (0.006 meter) one half the Length of tenth 

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

 ing to a point beneath anterior pail of lirsl dorsal, and thence gradual y d( ( leasing to tip 

 of tail. 



( at. No., U. S. National Museum, 2101 1 



i 



