244 



The observations set forth above (p. 1 18) 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. 



Young larva 



Metamorphosis 



Blastula Gastrula 



Diadema antillarum 



Aslropyga pulvinata 



Tripneustes esculentus 



Lylechinus variegalus 



anamexus 



panamensis 



Toxopneuxles pileolus 



Slrongylocentrotus pulcherrimus 



franciscantis 



Temnopleurus toreumaticus . . . 



Evechimts chlorolicus 



Heliocidaris luberculata 



erylhrogramma . . . 



Echinometra liicunter 



oblonga 



Colobocentrotus alratux 



Clypcasler japonicus 



Arachnoides placenta 



Echinarachnius e.rcenlricus . . . 



Encope micropora 



Mellila 6-per/orata 



Astriclypeus Manni 



Peronella Lexueuri 



Echinobrissus recens 



Brissus Agassizi 



Meoma grandis 



Ophiolhrix angulata 



Ophionereis squamulosa 



Astropecten xcoparius 



Aslerina pectinifera 



Gymnasteria carini/era ca 



Ophidiasler Guildingii 



Pisasler ochraceus 



Euasterias Troscheli 



Slichopux cali/ornicux 



I. stage 

 2 days 

 1 



1(2)- 



6 hours . . 1 



20 - (Vless) 24 hours 23 



II. stage heginniug completed 



12 days 

 5 



22 days 

 13 



5 



12 1820 hours 



24 

 14 

 14 

 18 

 15 



16 

 . 24 hours 2 days 



24 

 24- 

 24 



2 



23 



j 



2 days 



20 hours 

 1 day 



7 days (less?) 

 2 



5 

 4 

 4 



4 



ca. 15 



7 



40 45 hours 



1921 days 

 18 



ca. 6 



6 - 



