The dorsal arch has not yet been formed, and there is as yet no trace either 

 of a posterior transverse rod. That this latter rod will prove to exist 

 may be supposed from its existence in the two related forms described 

 below, and especially in the larva from the Gulf of Siam. which probably 

 belongs to T. toreumaticus. 



At the age of 12 days the larva had not developed beyond this stage, 

 and as I had then to leave Misaki. there was no possibility of studying 

 its further development. 1 

 tried to carry the culture 

 along with me; but while 

 1 succeeded in carrying 

 some other cultures in good 

 condition to Australia, this 

 one succumbed. 



In a plankton sample 

 from the Gulf of Siam (oil 

 Koh Kam, 4. II. 1900) I 

 have found an Echinoid 

 larva which is so very 

 similar to the larva of 



Temnopl. loreumalicus 1 ) 

 that it seems almost just- 

 ified to refer it to this 

 species. This larva is only 

 in a slightly more ad- 

 vanced stage than the 

 oldest stage of the T. to- 

 reumaticus larva reared. Vibratile epaulets are beginning to develop. 

 A posterior transverse rod has appeared and also the dorsal arch; on 

 the other hand the body rods have apparently not yet begun to be ab- 

 sorbed. Posterolateral processes are indicated, which will be supported 

 by the branches of the transverse rod; that this rod has branches at its 

 ends can be seen, but their definite form is not yet to be ascertained. 



l ) Till- fact that this larva was lakru in Ilir beginning of February, while tin- fertilizations 

 were undertaken in the end of June, does not render the referent -e "I the larva to this species 

 impossible, since some specimens taken oil Koh Kong in the (lulf of Siam on the 25th of 

 January 1900 prove to contain ripe sexual products. Whether Hiis species has then a breeding 

 season so Ions as indicated by these dales, or its breeding season is perhaps not so early in 

 Japan as farther South, remains to be ascertained. 



Fi.u. Hi. Skeleton of larva of Trnwnplcurux tnrrumatii'us. 

 '.> days old. 300 /i. Letters as in fig. .">. dtr. dorsal trans- 

 verse rod. 



