716 rnOCEEDINGS of hie national museum. vol. XXXII. 



almost spiny border; in dorsal perisome surrounding base of tenta- 

 cles, irregular elongated plates with many perforations; in tentacles 

 comparativel}^ very large irregular, curved perforated rods (or some- 

 times without perforations and spiny or branched); in finer branches 

 of tentacles smaller, very variable rather finelj' perforated plates. 

 Sole thin and translucent. Color in life: Ground color, very dull 

 light brown, the center of each scale being a darker brown; five oral 

 plates, a pinkish yellow ocher, light carmine at tips, the anal opening- 

 salmon pink. Length, slightly curved, 19 mm.; breadth, 16.5 mm.; 

 width of circle of oral valves, 7.5 mm.; distance from edge of oral 

 valves to edge of anal, 6 mm.; from center of oral aperture to center 

 of anal, 11 mm. 



LocaliUj. — Station 3863, Pailolo Channel between Maui and Molo- 

 kai islands, 127 to 15'± fathoms, broken coral, coarse gravel, rocks; 

 bottom temperature, 60'-'. One specimen on a lump of lava. 



Type.—QyX. No. 21225, U.S.N.M. 



Owing to the fact that the specimen is a trifle bent to conform to 

 the surface of the rock on which it was found, the breadth in the figure 

 is too great in proportion to actual length. The outlines of the scales 

 near margin are very inconspicuous, the plates themselves being very 

 tightly fitted together, although imbricating slightly, as do also the 

 middorsal plates. In addition to the granules the surface of scales is 

 regularly and microscopically roughened, giving under a magnifying 

 glass the appearance of tesselation. The series bordering sharp edge 

 of body is very small and free from granules. When the oral valves 

 are viewed from inner surface a rather narrow oblong scale or plate 

 is seen to be fitted over the radial suture between two oral valves, 

 there being thus five of these secondary oral scales. Their distal tips 

 are pointed, and from the exterior can be indistinctly seen between 

 the tips of the primary oral scales. On the inner surface at tip of 

 each secondary or inner oral valve is a small, pointed deciduous tooth- 

 like ossicle, the five points meeting in center of oral aperture. These 

 can not be seen from exterior at all. 



The plates in the sole are well spaced and the largest attain a major 

 diameter of 0.24: mm., although the majority are about 0.135 to 0.15 

 mm. The central perforations are usually the largest. Edge of plates 

 is undulating or marked by blunt lobes. Knobs are present on most 

 of larger plates, such as fig. \h^ but plates of the type of fig. \e (length 

 0.1 mm.) do not have them as a rule. At edge of sole the plates be- 

 come considerably larger (0.24 mm.) with relatively smaller holes and 

 more prominent undulations on maigin. The plates consequent!}' 

 appear stouter and heavier. The}' grade into the elongated rod-like 

 perforated plates of pedicles which attain a maximum length of 0.28 

 mm,, decreasing in size toward tip of pedicel. The plates in mem- 

 brane surrounding base of tentacles are especially distinguished from 



