77 



very obscure cross-bars of darker on the arms. According to a 

 colored sketch by Mr. Garrett, the tints of the living animal are 

 about the same. 



Variations. The characters of fifteen specimens which I have 

 examined were very uniform; only the young have shorter arms. 

 The proportions of the disc to the arms in specimens of different 

 sizes were 9.5 : 30; 16 : 68 ; and 19 : 93. The radial shields vary a 

 little in size and distinctness. 



This species seems, from descriptions, to be very near OpMolepis 

 imbricata ; it, however, has the arms a good deal longer, to which may 

 be added the different pattern of color. 0. imhricata has arms only 

 three times the diameter of the disc. 



Ophiolepis Gakretti, Lyman. 



Special marks. Arms six times the diameter of the disc ; not taper- 

 ing till just at the end. Mouth-shields as broad as long. 



Description of a specimen. Diameter of disc 9 millim. Width of 

 arm, without spines, 2 millim. Length of arm 55 millim. Mouth- 

 papilla3 five on each side, and one under the teeth, those on the sides 

 flat, stout, squarish, crowded ; the outer one sends a slender prolonga- 

 tion above and beside the next papillas. Teeth regular, broader than 

 long, with a rounded cutting edge. Mouth-shields neatly rounded 

 without, and with an acute angle within, length to breadth .9:1; 

 their outer edge is bordered by a line of little, crowded, angular pieces, 

 one of which is inserted between the mouth-shield and side mouth- 

 shield, at each corner. Side mouth-shields large, of equal width along 

 their length ; within separated bj^ one or two supplementary pieces. 

 Under arm-plates longer than broad, broader without than within ; 

 outer side curved, lateral sides re-enteringly curved ; length to breadth, 

 (7th plate) .9 : .7. Side arm-plates thick and swelled. Upper arm- 

 plates broader than long, broader without than within ; swelled, 

 length to breadth (19th plate) .5 : 1.3. The supplementary pieces are 

 small and crowded, the one at each outer corner being largest ; they 

 are at the base of the arm, from 7 to 10. The scaling of the disc is 

 very regular, the scales being a little smaller below than above ; 

 diameter of the largest nearly 1 millim. ; each has its free edge bor- 

 dered by a line of crowded and regular pieces, which are commonly 

 about seven in number. Radial shields irregular oval, separated by 

 two large scales one outside the other, and two smaller ones Ipng side 

 by side. Ai-m-spines 4 ; very small and slender, confined to the mid- 

 dle of the edge of the side arm-plate ; lowest one longest, 5 millim. 

 long. Tentacle scales two, rarely three, stout, thick, forming together 

 an oval figure, which stands obliquely to the length of the arm. 

 Color, in alcohol, disc pale reddish-yellow, with bands of darker on 

 the arms, below grayish. The living animal has a brick-red disc 



