672 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxii. 



of the subquadrate crown lacks a crosspiece. Occasionally the crown 

 is more circular. A much rarer form of table is shown in figure 2i?», 

 Plate LXIX. Here the disk is much reduced and the spire corre- 

 spondingly elongated. This form is apparently confined to the walls of 

 papilla' and to the center of tlie groups of rods, where there are com- 

 inonly three or four. The rest of the calcareous deposits are in the 

 form of small knobby rods or very incomplete buttons with knobs, the 

 principal forms being shown in the figures. They vary in length from 

 0.02 to 0.038 or 0.04 mm. Rareh^ there is a complete button 0.05 mm. 

 long. A characteristic feature of these deposits is their accumulation 

 in small circular groups or in small rings. They also form large 

 rings about the base of the ambulacral appendages. A relatively few 

 are scattered lietween the groups, Avhich are rather close together. 

 The supporting rods of the papilUe are curved with a spinous margin; 

 the tips being a trifle expanded, spinous, and commonly perforated. 

 At the tip of the papilhe the rods l)ecome smaller, laterally branched, 

 the branches sometimes joining to inclose meshes. Then the rods 

 resemble very open plates. Very rudimentary terminal plates appear 

 to be sometimes present. The papillae are further strengthened by 

 the peculiar long-spired, small-disked tables alread}^ mentioned. The 

 pedicels (of the ventral surface) have ver}" well developed terminal 

 plates, and in the vicinity of these are numerous bilateral curved ellip- 

 tical fenestrated supporting plates about 0.13 mm. long and with one 

 or two tiers of holes on either side of the central shaft. The margin is 

 often rough or toothed. The tables in the walls of the pedicels are of 

 the ordinary shape with a smooth margin. None of the slender 

 curved supporting rods found in the papilla are present in the 

 pedicels, except possibly on the transition area between pedicels and 

 papillee (lateral). 



This species is especiall}^ characterized by the form of the tables, 

 and the curiously knobbed, mostly incomplete buttons and rods, 

 arranged in circular groups and rings. It is very perplexing and 

 should probably be ranked inTheeV » IIo/ot/itc7'ia atra group'*' along with 

 grisea, inonuita.^ and others. The deposits, especiall}^ the knobbed 

 buttons and rods, are entirely difi'erent from those of atra or any 

 nearly related form. AnuUfera is also related to pervicax., perhaps 

 more closely than to atra. 



HOLOTHURIA FUSCO-OLIVACEA, new species. 

 Plate LXIX, figs. 3, 3«-/; Plate LXX, fig. 3. 



General form stout; subcylindrical. blunt at both ends. Mouth 

 directed ventrally ; anus terminal. Dorsal surface well arched and 

 covered with rather widely scattered papillae ; ventral surface well 



« Challenger Holothurioidea, Pt. 2, p. 213. 



