OPIIIOLEPIS ELEGANS. 59 



out than within, bounded within by a short, straight inner side, and two 

 inner laterals ; on the lateral sides by slightly re-entering curves, and 

 without by a curved or wavy outer side ; these plates somewhat resem- 

 ble the basal plates of O. j^aucispma ; first plate much ))r()ader than 

 long, nearly oval^ witli an inward projection filling the end of the 

 mouth-slit. Side arm-plates very regularly arched, occupying a portion 

 of the under surface of the arm more than equal to the width of the 

 under arm-plates. Upper arm-plates regular, broader than long, bounded 

 without and within by straight lines, and laterally by short curves ; 

 length to breadth (fourth plate), 1:2; farther out they become regu- 

 larly hexagonal, and, at the tip of the arm, fan-shape. Supplementary 

 pieces, long triangular, witli their point downward ; length to breadth 

 (seventh joint), .5 : 1. The arrangement of the upper plates of the disk 

 is extremely regular, and is as follows : in the centre a rosette of six 

 angular primary plates, of which the central one is the smallest, the 

 others having a diameter of about 2"""' ; from this group radiate five 

 interbrachial rows, each of three primary plates ; in the brachial spaces 

 there is a single primary plate, between the inner ends of the radial 

 shields and the central rosette ; each primary plate is surrounded by a 

 single line of about eighteen small angular scales, Ijdng on the same 

 level with the larger plates. Radial shields pear-seed shaped, their 

 points inwards ; large, somewhat swollen ; widely separated, without, 

 by a broad triangle of three scales, of wdiich the two outer ones are 

 rounded and much swollen, and within by a large scale, with its belt of 

 smaller ones ; a part of the above-mentioned primary plate also lies 

 lietween the inner ends of the radial shields ; their length to breadth is 

 3.2 : 2.2. Interbrachial spaces below covered without by a triangle of 

 three very large, much swollen scales, and within by three cross rows 

 of smaller and flatter scales ; the outer genital plate is much enlarged, 

 and makes a conspicuous ridge. Arm-spines, near base of arm, six ; 

 farther out, five ; very short, rounded, and blunt, scarcely tapering ; 

 lengths to that of under arm-plate, .3 (or .4) : 1. Tentacle-scales two, 

 forming together a nearly oval figure ; on the outer side of each pore 

 there is a stout triangular piece, that may be considered as homologous 

 with a similar part often found in Ophioglyi)ha ; besides this there is on 

 the basal pores a minute edge attached to the lateral side of the under 

 arm-plate. Color, in alcohol : below, pure white ; above, disk clouded 

 with pale greenish-gray and white, many of the primary plates sur- 

 rounded by a line of fine brown specks ; arms alternating with bands 

 of darker and lighter greenish-gray, the upper surface of the side arm- 

 plates being in the latter bands white. 



Variations. — The above description was taken from a Florida speci- 

 men ; three dried ones, from Charleston, S. C, seem to belong to the 



