REPORT ON THE OPHIUROIDEA. 239 



mouth papillae (as in Ophiomyces), and with a single row of slender, sharp teeth. On 

 outer joints of arms, near margin of each side arm plate, is a tuft of minute, translucent, 

 supplementary spines or pedicellariae, which have the form of a long-handled parasol. 

 They stand a little inside the true arm spines, which are continuous to the end of the 

 arm. 



Ophiotholia supplicans, Lym. (PL XXVIII. figs. 1-4). 



Ophiotholia supplicans, Lym., Anniv. Mem. Bost. Soc. Nat. Hist., pi. i. figs. 1-9, 1880. 



Three arm spines. Pedicellariae beginning about the ninth joint and arranged in 

 clusters of three or four. 



Diameter of disk (when the arms are raised vertically) 2 mm. Height of same 

 3 "5 mm. Width of arm without spines 0'8 mm. Length of arm about 13 mm. The 

 mouth angles are hig-h and narrow, so that the mouth slits between them are wide : with 

 their curved sides and sharp tooth at the apex the angles bear a resemblance to a bird's 

 head with a pointed bill. Three acute spine-like teeth, outside which, and partly encircling 

 the large three-sided jaw plate, as with a frill, is a transverse, curved, erect, close row of 

 eight or ten long, narrow, flat papillae. Again outside these, and on the jaws and mouth 

 frames are three parallel transverse rows of erect foliate papillae. The first row has six 

 papillae, which are smaller than some of those beyond, but, like them, flattened and widest 

 at the free end ; the second row is similar ; while the third usually consists only of two 

 papillae, much larger and wider than the others. These rows quite obscure the base of 

 the mouth angle and mouth shields. In general, the arrangement is that of Ophiomyces 

 frutectosus. The above numbers are the maximum ; some angles have fewer papillae ; 

 not more than four in a transverse row. In the fresh specimen, under arm plates are not 

 visible, but, on partial drying, their outlines may be seen. They are narrow, much longer 

 than wide, wider without than within, with a small angle within, lateral sides re-enteringly 

 curved, and outer side in a broken curve. In like manner the side arm plates are seen 

 to meet broadly below, and to form a slight spine crest at their outer edge. Figure 3 shows 

 the arm joint from below, so covered by the natural skin that the junction of the side arm 

 plates on the central ridge cannot be seen. Disk sugar-loaf shaped and sparsely set with 

 minute spines, each of which, in the partly dried specimen, is seen to stand on a small, 

 delicate scale. No radial shields visible, and there probably are none ; which, as in 

 Ophiomyces, may account for the fact that the arms are raised vertically, encircling the 

 high disk like a fence. Three sharp, slightly flattened, microscopically rough arm spines 

 nearly as long as a joint, standing near the outer edge of side arm plate, and on a low 

 spine ridge. At the ninth joint there appears, on inner side of spine ridge, and close to 

 base of spines, a cluster of three or four minute pedicellariae, scarcely 0'5 mix. long. They 

 are shaped like long-handled parasols, or slender-stalked agarics (fig. 4). with a long shaft, 



