MUSEUM OF COMPAKATIVE ZOOLOGY. 75 



broader within, where they meet. ' First under arm-plate transverse oval, 

 broader than long, often with lateral ends pointed ; second arm-plate four-sided, 

 with corners much rounded ; the next three are pentagonal, with an angle in- 

 ward, and outer edge curved ; beyond these the lateral sides become shorter, 

 80 that soon the form changes to very wide triangular, with a broad curved 

 outer edge, and an obtuse angle inward. Side arm-plates broad, little swol- 

 len, meeting below beyond the disk, separated above by upper arm-plates, 

 of which the first is oval, with pointed lateral ends ; those beyond four- 

 sided, broader without than within, outer side curved, lateral sides nearly 

 straight. Disk flat, smooth, and very thin ; upper surface covered with 

 small, irregular,* closely overlapping scales, with a row of larger scales 

 along the margin. Radial shields broad triangular, with edges rounded, 

 separated widely by a group of disk-scales ; length to breadth 2.3 : 2. On the 

 under surface the scales are more uniform, and are arranged in irregular trans- 

 verse rows, four to six in each row. The genital plate, except at its outer end, 

 appears only as a narrow line, bearing a close row of short, square papilla), 

 which become larger and more rounded where they form the arm-comb. 

 Three short, bluntly pointed arm-spines, situated near the junction of the side 

 ■with the under arm-plate. Seven square, close-set scales on each side of mouth- 

 tentacle pores ; the next two pairs have four on each side ; the next one usually 

 three on the inside and two on the other ; beyond the disk only one on the 

 inner side. Color in alcohol, white. 



Station 237, 1875 fathoms, 10 specimens. 



Ophioglypha undulata sp. nov. 



Plate III. Figs. 61, 63. 



Special Marks. — Three very short, conical arm-spines, standing on middle 

 of edge of plate. Disk-scales coarse and rather thick. Radial shields broader 

 than long, and joined. Papilla) of arm-comb close-set, flat, and with rounded 

 ends. 



Description of an Individual (Station 224). — Diameter of disk 12 mm. 

 Width of arm close to disk, without spines, 2.3 mm. Mouth-papilla) four on 

 each side, short and square and closely set, the outer one widest ; at angle of 

 the jaw usually a cluster of three conical papillae. Mouth-shield rounded tri- 

 angular, much broader than long, with an obtuse angle within, and outer side 

 slightly curved ; length to breadth 2.3 : 2.3. Side mouth-.'^hields nearly 

 straight, rather long, and meeting fully within. First under arm-plate oval or 

 rounded hexagonal, and wider than long ; the next longer than any other, axe- 

 shaped, with long lateral sides re-enteringly curved and outer side curved ; those 

 beyond grow rapidly shorter, and beyond the fourth are separated by the side 

 arm-plates, which are regular and scarcely swollen, and meet above and below 

 beyond the fourth upper arm-plate. First ujiper arm-plate wide, semicircular ; 

 the rest diamond-shaped, with ijiner angle truncated and the outer more or less 



