346 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [136] 



longer, acute central denticle and a smaller outer one, and with the inner 

 angle of the base slightly prominent ; the next to the outer lateral teeth 

 (fig. G, c) are much longer, broad, tapered, curved, acute; the outer 

 teeth (fig. G, d) are longer, more slender, more curved, triquetral, and 

 very acute, with a large basal lobe. A row of thin, distinct, roundish 

 scales (fig. G, e) forms a border outside the teeth. 



The pen (Plate XXVII, figs. 1-4) is thin, translucent, pale yellowish 

 in fresh specimens, but brownish or amber-color in alcoholic specimens. 

 It has a short, narrow, anterior shaft and a long, very thin, lanceolate 

 blade, which is concave beneath, especially posteriorly, for the edges 

 curve downward, but are not involute; the posterior tip is acute, a little 

 thickened, and slightly curved downward, so that the posterior end is 

 shaped something like the forward part of an inverted shallow canoe; 

 the cavity at the extreme tip is slightly decked over in large specimens. 

 In the male (fig. 4) the pen is relatively longer and the blade narrower 

 than in the female. The extreme anterior end is thin and flexible, and 

 rather sharply and abruptly pointed, being shaped like a pen ; the shaft 

 is rather stiff, with a strong, regularly rounded keel, convex above and 

 concave beneath ; outside of the keel the marginal portion curves out- 

 ward and then upward, so that its convex surface is below, and the 

 edge slightly turns up. The shaft, with its central keel and marginal 

 ridges, extends to the posterior tip of -the pen, decreasing regularly in 

 width beyond the commencement of the blade. The blade is at first 

 very narrow, and gradually increases in width ; it is marked by numer- 

 ous slightly thickened ridges, which diverge from the central lino as 

 they extend backward ; the edges are very thin. 



In the larger males the proportion of the greatest breadth of the 

 blade to the total length of the pen varies from 1 : 7.50 to 1 : 9.3G. In the 

 females it varies from 1 : 5.G0 to 1 : (5.10. 



The following description of the colors was made from a freshly caught 

 adult male specimen (1 G), taken in New Haven Harbor, May 18, 1880. 



Upper surfaces of the body, head, and caudal fin tliickly covered with 

 rather large chromatophores, which are mostly rounded or nearly cir- 

 cular, except along the middle of the back, where they are more crowded 

 and darker, and mostly have a long-elliptical form (perhaps accidental). 



The chromatophores, when expanded, are light red to dark lake-red, 

 varying to purplish red and pink; when contracted to small points, 

 they become brownish purple. 



On the head, behind the middle of the eyes, and toward the margin 

 of the caudal fin, the spots are smaller and less numerous, the interven- 

 ing bluish white ground-color showing more largely. Over most of the 

 dorsal surface the chromatophores are arranged more or less evidently 

 in circular groups ; usually the central chromatophore is a large, round, 

 dark-purplish spot ; this is surrounded by a circular space of whitish 

 ground-color, and by a circle of roundish chromatophores, mostly of 

 d ifferent shades of lake-red and pink, and a deeper lying circle of pale 



