56 



The skek'loii (Fig. 18) is ol the same lype as in the Trnmoplcurus aiul 

 Tcmnolrema hirva, the body rod being oidy soniewhal less elongale; it 

 is strongly liiorny. There is no hiiskcl siruclure. The recurrent rod is 

 not curved forwards (at least in (he single young larva preserved: 1 

 lia\e OMiitled lo observe how il was in (he specimens examined alive). 

 The postoral lod is I'encslraled. (Some irregularities are seen in I he 

 skeletal details tigured, hnl not so much as to obscure the main features.) 



At the age of 15 

 days the larva' had 

 readu'd their lull 

 size and weri' 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 a I their base, 

 rather abruptly nar- 

 rowed towards the 

 point. They are held 

 almost horizontally 

 and thus directly 

 serve as a Moating 

 apj)aratus. The fig- 

 ures do not show 

 these arms in their 

 natural position; Fl.N'lI, I'ig. 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 poslero-dorsal arms are seen half in profile; in reality 

 they are as wide as the ])Ostoral ones. PL VII, Fig. 2 is drawn from a 

 preserved specimen; the |)ostoral and ])ostero-dorsal arms have con- 

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

 more upright than normal. i) .\cross the base of each of these arms 

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



') I have thoufihl it of soine interest to represent the larva in preserved condition lieside 

 the figure of tlie livin}^ larva in order to sliow directly the nniounl of slirinkajfe due to preserva- 

 tion. Such shrinkage appears lo be unavoidable, especially in larvse with broad arms. e. g. 

 Ophiopluletis paradoxus, and must, of course, be taken into consideration when such larva- 

 are desciibed from preserved material. 



Fig. 10. Part of the skeleton (it a fully formed larva of Mespilia 

 (/Inbiiliis: front view', ■""'/i- I'oslerodorsal and anterolateral rods 

 as well as the dorsal arch have been oniitled. b. body rod; 

 po. postoral rod: |)lr. posterior transverse nxl : vir. ventral 



transverse rod. 



