— INTRODUCTION— 



During the Summer of 1838 it was jay privilege to occupy 

 the- Hopkins table in the U.S.F.C. laboratory atVWoods Holl 

 ' ile here I rediscovered the peculiar Ophiuran larva 

 which v:se first found and figur:cl by KROKN ( ). 



Finding the larvae he described in the open sea KROKN lid 

 not know to what species they belonged, but the larvae/,the 

 development of which is the subject of the greater part of 

 this paper, came from eggs laid in aquaria by Ophiura 

 brevispina. It is not likely that the same species of 

 Ophiuran occurs both at Funchal , where KROHN did his work, 

 and also at North Falmouth, where my material was obtained, 

 but it is very probable that species belonging to the 

 C-enus Ophiura have similar larval forms. 



Among Eehinoderms where a direct development from the 

 larva to adult occurs, that is: without the usual highly 

 specialized intermediate pelagic larva, we usually have 

 to do with a species which in some manner takes care of 

 ite brood, but in 0. brevispina the larvae are free-swim- 

 ming, they being provided with a well developed locomotor 

 apparatus, yet the usual Ophiurid pluteus larva is as com- 

 pletely omitted as it is from the life history of the vi- 

 viparous Amphiura squamata. 



From the fact that the usual pluteus skeleton is begun 

 in the larvae of D. brevispina one ie lei to suspect. that 

 at some period in its history, the species possessed a 



