34 K. MITSFTUTJ : RTrDIES ON 



is produced in contracted specimens. Iîi young specimens the 

 number of pedicels in this ambulacrum is rather small. Lat- 

 eral ventral ambulacra with pedicels in double alternate row, but 

 more crowded in the middle parts. On the dorsum, rather large 

 conical papillae on each of the two dorsal ambulacra. They appear 

 to form a double or a zigzag row in large specimens, but are in a 

 single row in small specimens. 



The peculiar structure of this species consists in the low warts 

 referred to by Thkel. On the two lateral dorsal interambulacra 

 and on the ventral surface, outside the lateral rows of pedicels, 

 there are seen a number of white spots, especially numerous in 

 the middle parts of the body. Theel has remarked that these 

 look like contracted pedicels, but are different from them in that they 

 are utterly devoid of any calcareous deposits, end-plates, or other 

 calcareous bodies. These statements I am able to corroborate. 

 The spots or bodies in question are simple fungiform papillae, 

 most of which possess each a single small spicule in the centre, 

 probably representing a rudimentary end-plate (textfig. 7 e). It 

 seems to me that the papillae are a peculiar modification of 

 ambulacral appendages. 



Polian vesicle one, large. Genital bundles two. Respiratory 

 trees in two branches, no reie mirahile. 



Calcareous deposits are remarkably uniform. There seems to 

 be no difference between those of tlie dorsal and ventral surfaces, 

 nor between those of the anterior and posterior parts of the body. 

 They consist almost entirely of four-armed tables 0.12 mm. in 

 diam. {a — c). The spire consists of four columns wliich are united 

 some distance below the tip {b). The tips end in four fi'ee teeth. 

 Near the top of dorsal papiUae, the spire is more slender, and 

 higher (0.070 mm.), and the basal part more vaulted (c). Supporting 



