138 BULLETIN OF THE 



breadth .8 : 1. Side mouth-sliields short and rather wide, meeting within. 

 Under arm-plates pentagonal, wider than long, with a very obtuse angle in- 

 M'ard, sometimes modified as a curve ; lateral sides a little re-enteringly curved, 

 and outer side gently curved. Upper arm-plates wide fan-shaped, with an an- 

 gle inward. Side arm-plates stout, rather prominent, narrowly meeting above 

 and below, near base of arm. Disk slightly puffed and wrinkled, closely set 

 with small, round, smooth grains, among which, on upper surface, appear a 

 few short stout spines ; radial shields and disk-scales hidden by skin and by 

 granulation. Seven regular, slender, cylindrical, tapermg, not thorny arm- 

 spines ; lengths to that of an arm-joint 2.8, 2.5, 2, 2, 1.5, 1.3, 1 : .8. One 

 pointed, rather large tentacle-scale. Color in alcohol, white. 



A smaller specimen had a disk 6 mm. in diameter vnth grains, but scarcely 

 any spines on it. A young one had a disk 4 ram. in diameter, and arms, 

 16 mm. long. The disk-grains were rough under the microscope ; the arm- 

 spines were proportionately longer, and the side arm-plates more prominent, 

 than in the adult ; the outer mouth-papilla was larger than its neighbors. 



Station 171, 600 fathoms, 2 and 2 young specimens. 



Ophiacantha granulosa sp. nov. 



Plate Vm. Figs. 206 - 208. 



Special Marks. — Disk evenly set with smooth grains ; outer ends of radial 

 shields naked ; ten smooth slender arm-spines. 



Descrijition of an Individual (Station 201). — Diameter of disk 9 mm. Length 

 of arm 42 mm. Width of arm without spines 3 mm. Seven pointed, rather 

 stout, nearly cylindrical mouth-papilla5. Seven teeth, flat, ■with a rounded 

 cutting edge. Mouth-shields small, broader than long, with an obtuse angle 

 within, and a curve without ; length to breadth .8 : 1. Side mouth-shields 

 lai^e and wide, broader without than within, where they are slightly separated. 

 Under arm-plates much wider than long, of a wide axe-shape, with a curved 

 edge outward, a lobe or a narrow obtuse angle within, and the lateral sides 

 re-enteringly curved. Upper arm-plates rather small, of a wide fan-shape, 

 with an angle inward, and lateral sides re-enteringly curved. Side arm-plates 

 large and moderately projecting, meeting broadly above, near base of arm, but 

 scarcely touching below. Disk slightly puffed, closely and evenly set with 

 smooth grains, about four in the length of a nmi., which hide the fine disk-.scales, 

 except in the lower interbrachial spaces. Radial shields covered, except their 

 outer ends, which are naked and sunken below the surrounding surface. Ten 

 slender, tapering, cylindrical, translucent arm-spines, which are not thorny ; 

 lengths to that of an arm-joint 3.2, 3.2, 2.2, 2, 2, 2, 1.8, 1.3, 1.3, 1 : 1. One 

 rather small, blunt tentacle-scale. Color in alcohol, pale reddish-brown. 



A younger .specimen, with adi.sk 4 mm. in diameter and an arm of 18 mm., 

 presented no special variation.s, except that there were only eight arm-.spines, 

 and the under arm-plates were proportionately smaller. 



Station 201, 82- 102 fathoms, 8 specimens. 



