24 



'I'hc obscrvalions si't lurlli above (p. 1 l<S) liMi(liiit> lo \m)\r Iho i-xislence 

 ol' a c-asc ol' Inie inclagenesis in an Opiiiuioid-laiva, Ophioplulfus opu- 

 lenliis, may be recalled here. Allhoui*!) this is certainly quite an isolated 

 case in Mchinodernis, considerable iiilt'ii'sl is attached to it both tioni "a 

 nior|)hological and a biological point ot view. 



The observations on the developnienl ol' tlie 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 lo 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. 



Diadcinu aiililloruni 



Aslruptjya putvinata 



Tripneiistes esculenlus 



Lytechiniis varieyalns 



anainfsiis 



pananwnsia 



Toxopneusles pileolus 



Slrongijlocentrotus pulcherrimus 



/ranciscaniis 



Tcinnoplrnrtis Idrfumalicua . . . 



lu'ichiniis chloruliciis 



Heliocidaris liihinulald 



erylhroi/ramnia . . . 



Echinomrtra hicunler 



— (il'ldiiga 



Colobocinlrolus alradis 



Clypeasler japonicits 



Arachnoides placenta 



luhinarachniii.s exccnlriciis . . . 



Encope micropora 



Mfllild li-jxr/orala 



Aslriciypeiis Maiini 



f'cronella Lcsiicuri 



Echinobrissus recens 



Brissus Agassizi 



Meoma yrandis 



Ophiolhri.v anyiilala 



Ophiontreis squannilosa 



Astropecten scopariif< 



Asterina peclini/cra 



Gyninasleria cariiii/ira ra. 24 



Ophidiaslcr Giiildinyii 



Pisaster ochraceus 



Euaslerias Troscheli 



Stuhvpus cali/iirnicits 



