12G BULLETIN OF THE 



without than within, four-sided, having lateral sides re-enteringly curved and 

 a peak without ; those beyond are similar, but nearly pentagonal. Side arm- 

 plates broad and thick, meeting below beyond the fourth under arm-plate and 

 above beyond the second upper arm-plate, which is fan-shaped, with an angle 

 inward. Disk flat and rather thin, covered with stout, rounded, microscopically 

 tuberculous plates, whereof a large primar}' occupies the centre, with five others 

 about it, separated in the interbrachial space by a radiating row of two or more 

 scales ; outside these, again, is a row of ten semicircular plates with small scales 

 between ; near each interbrachial margin are two plates side by side ; on the 

 lower interbrachial space are three transverse rows of irregularly shaped plates. 

 Genital scales composed of three irregular pieces placed end to end. Genital 

 openings extending from outer edge of mouth-shield to margin. Two short, 

 stout, blunt, tapering arm-spines placed low on the side arm-plate, the lower 

 one twice as long as the upper and about half as long as an arm -joint. One 

 large rounded tentacle-scale on the inner side of the tentacle-pore. Color in 

 alcohol, pale gray. 



A young with a disk of 2.8 mm. had arms 5 mm. long. The disk was 

 more ai-ched, and its plates, of course fewer, were microscopically tuberculous. 

 The side mouth-shields were very large and swollen, and the mouth-shields 

 small. The first under arm-plate larger than in the adult, and the rest much 

 smaller proportionately. 



Station 1(38, 1100 fathoms, 12 -j- specimens. Station 169, 700 fathoms, 

 12 + specimens. 



Ophiozona insixlaria sp. nov. 



Plate VI. rigs. 149-151. 



Special Marls. — Four short, nearly equal arm-spines. Arm high. Side 

 arm-plates swollen, and strongly flaring outward. Radial shields large, 

 rounded triangular, widely separated. 



Description of an Individual (Station 173). — Diameter of disk 6 mm. 

 Length of arm about 18 mm. Width of arm close to disk, without spines, 

 1.6 mm. Five short, squarish, close-set mouth-papillae on each side, one large 

 spearhead-shaped at apex of angle. ^louth-shield longer than broad, with a 

 very deep curve without, and an angle within ; length to breadth, 1 : .8. Side 

 mouth-shields .short and thick ; rather wider without than within, where they 

 meet. First under arm-plate very small, transverse oval in shape ; second, 

 third, and fourth plates large and five-sided, with inner angle truncated, small 

 re-entering curves on the lateral sides, and outer edge slightly curved ; beyond, 

 they ai>proach a fan-shape, with an angle inwanl. Side arm-plates broad, 

 swollen, and flaring outward, just meeting below beyond the fifth under arm- 

 j)late, and above beyond tlie fifth or sixth arm-])latc, which is fan-shajied, with 

 an angle inward. Disk rounded ]x'ntagonal and flat, with a large central plate, 

 and five othei*3 round it, separated from each otiier by a wedge-scale ; inter- 

 brachial spaces filled by four angular plates, a large one within, outside this 



