12 



iiK- U) join llu' "I liiienioa" on ils trip roiiiid tlu' Xoitii Island of New 

 Zealand, and to the Direcloi ol liu" (;aiiu',t*ie Inslilnle lor allowing 

 me to inehide in this report the resnlls obtained (hiring the I'^xpedilion to 

 Tobago \i. \V. I. h'or the hospitality olTered me I'rom the I'hilippine, 

 the .Jajjanese and the Australian (lovernment 1 shall liave to Liiank at 

 another occasion, having to confine myself at present lo what has a con- 

 nection willi the j)resent work. 



It may be practical, and useful, lo give here a short summary of what 

 has been accomplished hitherto in the study of the larval forms of the 

 different species of fkhinoderms, either b}' direct rearing of the larvae or 

 by identifying the pelagic larvEe found in the plankton, tracing their 

 origin through combinations of known facts. 



From this summary are omitted all larv;e not traced wilii any reason- 

 able degree of certainty to their parental forms. Further viviparous 

 forms or such as j)rotect their young, the embryos not having a free or 

 pelagic stage, are not mentioned. Likewise such cases, where only I lie 

 postembryonal stages are described (e. g. several species of Comalulids), 

 are omitted from this summary. Observations relating only to tlie fertili/.a- 

 lion, cleavage and gastrulation, but not carried so far as to (he beginning 

 larval form are generally not considered either; further generally no men- 

 lion is made of the great number of papers relating to ex|)erinienlal 

 studies on the larvae — treatment with various chemical agents, hybridiza- 

 tion etc. — , except in cases where also pure bred larvje are reared. 



The enumeration of the species mentioned follows the systematic ar- 

 rangement, not the chronological order of the observations. The arrange- 

 ment is that adopted in the special part of this work, beginning with the 

 Fchinoidea. 



I. Echinoidea. 



Cidaris cUlaiis (L.) (Syn. Durocidaris papilUila): reared until nearly Ihe 



full larval shape by Prouho, 1888. 

 Arbacia lixula (L.) (Syn. Arbacia pustulosa (iray; Echinocidaris a^qui- 



tuberculata (Blv.)); reared by W. Busch, A. Krohn. 1853, 18.>4, 



to fust larval stage; the fully formed, pelagic larva identified by 



.Job. Miiller, 1853; reared through metamorphosis by (iiesbrechlj 



1909 (in v. ITbisch, 1913). 

 Arbacia punctulala (iray; reared to full larval shape by Fewkes, 1880; 



to full larval shape by Brooks, 1882. Ilii'ough metamorphosis by 



Carman & Colton, 1882. 

 Psainmcchinus miliaris (Miill.) (Syn. Echinus, I'ai echinus miliaiis); pelagic 



