56 



The skeleton (Fig. 18) is of the same type as in the Temnopleurus and 

 Temnotrema larva, the body rod being only somewhat less elongate; it 

 is strongly thorny. There is no basket structure. The recurrent rod is 

 not curved forwards (at least in the single young larva preserved; I 

 have omitted to observe how [it was in the specimens examined alive). 

 The postoral rod is fenestrated. (Some irregularities are seen in the 

 skeletal details figured, but not so much as to obscure the main features.) 



At the age of 15 

 days the larvae had 

 reached their full 

 size and were in the 

 beginning of meta- 

 morphosis. It is now 

 a most striking ob- 

 ject and one of the 

 most beautiful Echi- 

 noderm larvae. The 

 postoral and postero- 

 dorsal arms are very 

 wide at their base, 

 rather abruptly nar- 

 rowed towards the 



==^ >^~\\ ^ r\-\ point. They are held 



/A m W* almost horizontally 



Fig. 19. Part of the skeleton of a fully formed larva of Mespilia 

 globulus; front view. 300 /i. Posterodorsal and anterolateral rods 



and thus directly 

 serve as a floating 



as well as the dorsal arch have been omitted, b. body rod; apparatus. The fl'- 

 po. postoral rod; ptr. posterior transverse rod; vtr. ventral 



transverse rod. un?s d not sh W 



these arms in their 



natural position; PI. VII, Fig. 1, which was drawn from a living specimen, 

 shows the larva in half dorsal view; the postoral arms are seen in their 

 full breadth, while the postero-dorsal arms are seen half in profile; in reality 

 they are as wide as the postoral ones. PI. VII, Fig. 2 is drawn from a 

 preserved specimen; the postoral and postero-dorsal arms have con- 

 tracted to less than half their natural width and also the position is 

 more upright than normal. 1 ) Across the base of each of these arms 

 is a large ciliated epaulet. In the preserved specimens the epaulets 



') I have thought it of some interest to represent the larva in preserved condition beside 

 the figure of the living larva in order to show directly the amount of shrinkage due to preserva- 

 tion. Such shrinkage appears to be unavoidable, especially in larvffi with broad arms, e. g. 

 Ophiopluteus paradoxus, and must, of course, be taken into consideration when such larvae 

 are described from preserved material. 



