244 



The observations set forth above (p. 148) tending to prove the existence 

 of a case of true metagenesis in an Ophiuroid-larva, Ophiopluteus opu- 

 lentus, may be recalled here. Although this is certainly quite an isolated 

 case in Echinoderms, considerable interest is attached to it both from a 

 morphological and a biological point of view. 



The observations on the development of the various forms studied in 

 this work convey a good impression of the great diversity obtaining, as 

 regards the length of the time required for the development. 

 Although I have not taken care in all cases to notice the exact time at 

 which each stage of development was reached, still a good deal of inform- 

 ation may be gathered from what has been noticed. It may be practical 

 to give the facts in a tabular form. 



Diadema antillarum 



Astropyga pulvinata .' . . . 



Tripneiistes esculentus 



Lyiechinus variegatus 



— anamesus 



— panamensis 



Toxopneustes pileolus 



Strongylocentrotus pulcherrimns 



— franciscaniis 



TemnopleuTus toreumaticus . . . 



Evechinus chloroticus 



Heliocidaris tuberculata 



— erythrogramma . . . 

 Echinometra lucunter 



— oblonga 



Colobocentrotus atratus 



Clypeaster japonicus 



Arachnoides placenta 



Echinarachnius exceniricus . . . 



Encope micropora 



Mellita 6-perforata 



Astriclypeiis Manni 



Peronella Lesueuri 



Echinobrissus recens 



Brissus Agassizi 



Meoma grandis , 



Ophioihrix angulata 



Ophionereis squamulosa 



Astropecten scoparius 



Asterina pectinifera 



Gymnasteria carinifera ca. 



Ophidiaster Guildingii 



Pisaster ochraceus 



Euasterias Troscheli 



Stichopus califnrnicus 



