NO. 3 DEICHMANN : HOLOTHURIOIDEA ; PART I, DENDROCHIROTA 105 



siblj' have reached its full size. Other members of the genus, as for ex- 

 ample Thyone fusus, reach a considerably greater length. 



Thyone neofusus resembles Thyone fusus? from the West Indies 

 (Deichmann, 1930, p. 167) but differs in the complete lack of a spire 

 on the supporting plates; this may of course be a variable character. For 

 the present it seems natural to segregate the various forms of fusus until 

 different material has been gathered to permit a critical survey. So far 

 no closely related species have been reported from the Californian and 

 Chilean waters or from Hawaii. 



2. Thyone bidentata, new species 

 Plate 18, Figs. 13-16; text figure 4 



Diagnosis. — Small form (few cm. long) with delicate to fairly stout 

 feet, often in distinct bands and also scattered in the interambulacra. 

 Inner anatomy typical of the genus. Spicules tables with oval to lozenge- 



I I I I I I I I I I I I I I I I 



Text fig. 4. Thyone bidentata, new species, juv. 

 1-3. Tables from integument. 

 4. Supporting table from tube foot. 

 Scale, i/ioo nim. 



shaped disk with 4 central holes (and a few holes in the ends when the 

 disk is lengthened) ; spire tapering to a cone with few teeth. Supporting 

 tables with spire composed of 2 rods united into a slender spine, ending 

 in 2 diverging teeth. Introvert with tables with numerous holes and low 

 spire with diverging teeth; tentacles with a few rosettes. Color of pre- 

 served specimens pale brown. 



