60 



lance to the Mesfjiliu-lavya, this larva must in all probability belong to 

 some Tenmopleurid. possibly a Snlnvicis. 



Echinopluteus of Temnopleurid (?), species c. 



IM. XI. Fig. A. 



Together willi llu' specimen ol llie species a were IoiiikI. in the same 

 plankton sample Irom ofT .Jolo, three specimens of another Echinopliileus 

 species, which must be assumed to belong likewise to a Temnopleurid, 

 antl which 1 shall designate as species c. One of these specimens has not 

 yet begun to metamorphose, the two others are in the beginning of meta- 

 morphosis. Although not in a very good state of preservation the younger 

 of these specimens shows several very characteristic features well; it was 

 therefore thought desirable to give a whole figure of it, although it had 

 to be partly restored: thus the vibratilc band is preserved only in the lower 

 part of the arms, so that the true shape of the arms cannot be seen; like- 

 wise it is impos.sible to ascertain the exact shape and size of the epaulets. 



As seen in PI. XI, Fig. 3 the absorption of the body rods has not yet 

 begun, in spite of the fact that the posterior transverse rod has already 

 been formed. The body is thus seen to be somewhat elongated as in those 

 Temnopleurid-larvee of which the young laival stage is known. .\ very 

 characteristic feature of this larva is the shape of the anal lobe, which is 

 very high, being supported by the very long ventral transverse rods; it 

 is concave in the middle, the corners being rather prominent. On the dor- 

 sal side the vibratilc band is |)ro(luced into a small lobe, supported by a 

 process from the dorsal arch. The postero-lateral process is very short and 

 small, but it is quite possible thai it is considerably larger in the living larva. 



The skeleton (Fig. 22) affords several very characteristic features. 

 The body rods are branched at the end in the same way as appears to be 

 the rule in Temnopleurids. The postoral rod is fenestrated, but the holes, 

 which are ver}' small, disappear completely a lit lie above the middle of 

 the rod, and the outer part is simple, the three component rods coalescing 

 .so completely that there is no trace of a compound structure. The postero- 

 dor.sal rod is simi)le, slightly curved. Both these rods are very sparsely 

 set with line thorns. There are two sets of ventral transverse rods, one 

 very long, upwards directed, supporting the high anal lobe, the other 

 transversely directed, short: the latter ma\ perhaps really represent llu" 

 recurrent rod. The posterior transverse rod is very peculiar, formed like 

 a bow, with no posterior branch at the ends; on the other hand it has a 

 long posterior |)rocess in the middle, somewhat curved, and a small an- 

 terior process. In PI. XI, Fig. .3 it is seen to have developed before the 

 absorption of the body rods has begun; a similar case was found in the 



