114 THE APODOUS HOLOTHUKIANS 



KEY TO THE SPECIES OF CHIRIDOTA. 



A. Wheel-papillae numerous, more or less uniformly scattered all over the body, with no 

 evident arrangement in longitudinal series; digits 8-14. (In young specimens, pa- 

 pillae may be very few on ventral side.) 



B. Numerous curved rods (plate vii, fig. 27), with more or less branched ends scat- 

 tered all over interambulacra ROTIFERA 



BB. No such rods in interambulacra. 



Miliary granules of longitudinal muscles, minute oval particles; polian vessels 



5-10 FERNANDENSIS 



Miliary granules of radii longer than diameter of wheels; poliau vessels 15-20. 



STOHLMANNI 



A A. Wheel-papilla? numerous or few, confined to interambulacra, and there forming more or 

 less irregular longitudinal series, less abundant on ventral side and often wholly 

 wanting there. 

 B. Digits of tentacles about 20; wheel-papillae in 5 irregular series; numerous minute 



crescent-shaped bodies in skin VIOLACEA 



Bli. Digits of tentacles generally fewer than 16 (very rarely 18). 



C. Wheel-papillae very few and only in right and left dorsal interambulacra ; stel- 

 late, perforated plates (plate vii. fig. 25) in skin MARENZKI-LERI 



( 'C. No stellate plates in skin. 



D. Numerous "buttons" ("schnallenformiger Hautkalkkorper") in skin; 



wheel-papillae in 5 simple longitudinal series . . . . . EXIMIA 



DD.No "buttons" in skin. 



E. Curved rods, with enlarged ends (plate vii, figs. 16 and 27), which 

 may be smooth or spinous, or even branched, scattered in skin, 

 at least along ambulacra. 



F. Size large, up to 200 mm. ; color more or less purple ; wheel- 

 papillae confined almost wholly to mid-dorsal interambulacrum. 

 Curved rods very small (40-60 p.), confined to ambulacra, 



and distinctly curved REGALIS 



Curved rods larger ( 80-120 /*), uniformly scattered, and 



commonly almost straight UNISERIALIS 



FF. Size small, under 100 mm.; color not purple; wheel-papillae and 



rods more or less generally present in all the interambulacra. 



Color red or reddish ; wheel-papilla numerous dorsally ; 



occurs about coral reefs RIO IDA 



Color whitish; wheel-papilla; in an irregular single row in 

 each interambulacrum : occurs in mangrove swamps. 



INTERMEDIA 



HE. No such curved rods in skin. 



F. Size small, usually, under 100 mm. (rarely twice that) ; color in 

 life yellowish, pink, red or purple, becoming whitish, grayish, 

 yellowish, dusky or purplish red in alcohol ; wheel-papillae, of 

 course, white. 



Wheel-papilla?, very large, 1-1.5 mm. in diameter; polian ves- 

 sels few, only 4-5 ; austral PISANII 



Wheel-papillae smaller and polian vessels numerous, 10-20 or 



more ; boreal L^VIS 



FF. Size large, up to 300 mm. ; color prevailingly grayish, with more 

 or less red pigment in skin DISCOLOR 



