72 OPHIOCOMA PUMILA. 



about twelve, in four irregular horizontal rows ; stout, rounded, a little 

 longer than broad, pretty closely set. Teeth four, longer than broad, 

 flat, square, inner edge narrower than outer edge ; two middle ones 

 largest, upper one much narrower than others. Mouth-shields rounded 

 square, a little longer than broad ; length to bre. 1th, 1.5 : 1.3. Side 

 mouth-shields extremel}^ small, variable in size, occupying a triangular 

 space between outer part of mouth-shield and innermost arm-plate. 

 Under arm-plates more or less octagonal, those lying within the margin 

 of disk smaller than those just beyond. Innermost plate rudimentary, 

 scarcely larger than moutli-papill» next it ; second plate nearly square, 

 with outer corners rounded, length to breadth, .8 : .8 ; next three plates 

 nearl}^ regular octagons ; eleventh plate slightly curved without, lateral 

 sides straight, inner laterals rather longer than inner side proper, length 

 to breadth, 1.1 : .9 ; this is the common shape of the under arm-plates, 

 and is retained till very near the tip of the arm. Side arm-plates en- 

 croaching somewhat on both upper and under arm-plates. Upper arm- 

 plates very broad heart-shaped, outer side and corners regularly curved, 

 inner laterals sloping towards each other, and nearly meeting Avithin. 

 First plate rudimentary, and nearly covered by granulation of disk ; 

 second, third, and fourth plates more or less oval, and all smaller than 

 those that immediately succeed ; sixth plate of usual shape and size, 

 length to breadth, 1,2 : 1.7 ; this proportion holds the same (though the 

 plates grow smaller) close to the tip of the arm. Granulation of upper 

 surface of disk rather coarse, grains shaped like mouth-papilla?, some 

 longer than their neighbors, about 30 to a square mm. Granulation 

 extended on arm so as nearly to cover first upper arm-plate ; below, a 

 broad naked belt parallel with genital slits ; remaining triangular space 

 granulated, quite up to mouth-shields ; grains less close and rather more 

 tooth-like than those above. Edges of genital slits more or less finely 

 toothed. Arm-spines neatly rounded and tapering, slightly flattened. 

 Second and third joints, three slender flattened spines, about .7""°' long ; 

 fourth and fifth joints, four spines, about 1.2""°- long ; sixth, seventh, 

 eighth, and ninth joints, five spines ; tenth joint, four spines, decreasing 

 in length and thickness from above below ; length of upper spine to 

 that of lowest, 2 : 1.3 ; two upper spines considerably stouter than two 

 lowest. This number and proportion holds till near the tip of the arm ; 

 the spines grow more slender, however, and the second is sometimes 

 longer than the upper one. Close to tip of arm only three spines. 

 Tentacle-scales pointed oval, hke a broad spear-head ; on second, third, 

 and fourth joints two, on rest only one. Color, in alcohol : above, van- 

 dyke brown, paler towards centre of disk ; arms banded with lighter, 

 each band occupying two or three joints ; also some white spots on 

 edges of upper arm-plates ; below, very faint brown ; chewing apparatus, 

 mouth-shields, and under arm-plates nearly white, the latter often with 



