Echinopluteus of Temnopleurid (?), species b. 



From the (iulf of Siam (ofT the North of Koh Kut, 27/1. 1900), there 

 are two larva? in an advanced stage of metamorphosis, which represent 

 another closely related species (Fig. 21). The posterior transverse rod 

 is shorter and the lower branches have fewer thorns than in species a; 

 the small inner branches are lacking. The irregularities of the upper 

 branch seen in the figure are, evidently, abnormal: they are not seen 

 in the second specimen. The posterodorsal rod is distinctly curved 



Fig. 21. Skeleton of Temnopleurid larva, species b: fronl view. --" ,. Tin 1 widening ol I In- 

 dorsal and ventral transverse rods are probably due to the hi-ginnin^ metamorphosis. 



Letters as in fii>. 20. 



and, like the postoral rods, densely serrate. Both these rods are 1'ene- 

 st rated in their whole length. The dorsal arch has the same shape as in 

 species a, only the posterior prolongation appears to be shorter. In one 

 ol' the specimens muscles are seen very distinctly to pass between the 

 ends ol the body rods, which proves that the four main arms in this 

 species may be moved and probably are kept in a nearly horizontal posi- 

 tion while swimming, as in the Mes[>ili<i-\i\r\i\. That vibralile epaulets 

 are present as in the .1/r.sy;/7/V/-larva can be ascertained, otherwise the 

 shape of the larval body cannot be seen distinctly on account of the ad- 

 vanced stage of metamorphosis. 



As with species a it can only be said that, judging from the close resemb- 



s* 



