15 



by these points. 'Vhv posterodoisal rods Iinve just appeared; they are 

 fenestrated. The dorsal arch has a very h)iiL( posterior process; the fact 

 of its appearance at this comparatively yoiiiig stage woidd seem to indicate 

 that liie arms, except the postoral ones ( they are broken in the spe- 

 cimen, so that their exact length cannot be ascertainetl; but they arc 

 fairly long, anyhow — ) are, upon the whole, short. The anterolateral 



Fig. 11. Skfk'toii (>r llu' larva of Toxupnetistes rosciis ('!). --^/,. Lellers as in lig. 5. 



arms (they arc broken, but somewhat restored in tiic llgure) are evidently 

 short. The posterior transverse rod has not yet appeared. The body 

 skeleton is nearly smooth (Fig. 11). 



Pseudocentrotus depressus (A. At).). 



As the breeding season of this species did not occui- (hiring my slay 

 in .Japan (Aj)ril — July), I could not study its ilevelopment myself. Being, 

 however, very anxious to learn, whether the larva of this species would 

 prove to be of the same type as the other Toxopneustids, as I expected, 

 or perhaps of the Echiims-Slronfii/loccnlioliis type, 1 asked my Japanese 

 colleagues to do me the service lo try to rear the larva, when its breeding 

 season came on. Dr. Fujita. then .Assistant at the Biological Station 

 of Misaki, kindly undertook lo icai- Ihe iaiva. when in the end of Oc- 

 tober ripe specimens of the species were found. Tiu' preserved larva- 

 were sent lo me and received in hVbruary 1!)1() in Panama. On exami- 

 ning liiem 1 found my expectations confirme<l: Ihe body skeleton formed 

 a basket structure as in the roxo|)iieuslid;e (i. v. most of them, LijUxhi- 

 luis forming a remarkable exce|)lion). The closer study of the larva', 

 which were reared only till I he lirsl stage (the oldest being 10 days old). 



