546 



TH. MORTENSEN : DE VELO I'M K NT OF 



and look somewhat like the antlers of a stag (Kig. i). The rods of 

 the postoral and the postero-dorsal processes are fenestrated. There 

 are four vibratile lobes, but no epaulettes. 



It is evident that this larva does not suggest any relationship 

 with that of Strong, pidcherrimus. On the other hand, my conclu- 

 sion that Toxocidaris belongs to the Echinomet rides gets, for the 

 present, no support from the structure of the larva. No Echinometrid- 

 larva is known with certainly as yet. I have described in the 

 „ Festschrift für Spengel " a very curious larva from the West 

 Indies, with a pair of extremely long lateral processes, which larva I 

 think must be referred to Echinometra lucunter. It is certainly very 

 different from that of Toxocidaris tuberculatus. But so long as we 

 know so very little of larvae within the family Echinometridœ, it is of 

 course impossible to draw any conclusion from the shape of its larva 

 against the position of Toxocidaris within that family. 



Temnopleuridce. — Hitherto there was not known any Temnopleurid- 

 larva. I was therefore very satisfied in getting the opportunity of 

 rearing the larvae of three different Temnopleurids, viz. Temnopleurus 

 torenmaticus, Pleurechinus sp. and Mespilia globulus. They all 

 agree in the structure of body skeleton : the main rod has a 

 median process off the posterior end of the stomach, and beyond 

 this process there is a short prolongation, which becomes absorbed 

 in the later stages. The postoral and postero-dorsal rods are 

 fenestrated. 



These larvae tend to show that there is a special type of larva 

 within the family of Tcmnoplcuridœ, characterized mainly by its 

 body skeleton. As might be expected, they differ from one another 

 in several minor points ; but I cannot enter here on these details. 

 The larva of Mespilia is one of the most beautiful larvae of Echino- 

 derms known to me. The four main processes are very wide, with 

 epaulettes across their base ; there is a posterior cross-rod, ending in 

 small branching postero-lateral rods. Of the two other forms I have 



