52 BULLETIN OF THE 



16. No ventral embryonic row of spines or plates was observed in 

 the genus and species studied. 



17. Genitals of Asterias are thought to be homologous with "basals " 

 of Amphiura. 



18. First interbrachial (odontophore) is homologous with the orals 

 of Amphiura. 



19. Madreporic opening is placed on two homologically different 

 plates in Asterias and Amphiura. 



20. 1st. Genitals; 2d. Dorsocentral ; 3d. Dorsals; 4th. Interarabu- 

 lacrals ; 5th. Terminals; — represented in Amphiura by, 1st. Basals; 

 2d. Dorsocentral; 3d. Dorsals; 4th. Laterals; 5th. Terminals. (Ho- 

 mologous plates numbered the same.) 



21. Oral ambulacrals of Asterias are represented by the "spoon- 

 shaped plates" of Amphiura. 



22. " First and second adambulacrals " of Amphiura have no homo- 

 logue in the mouth parts of Asterias. 



23. Ventrals of Amphiura are not represented in Asterias. 



24. Dorsolaterals and connectives of the arms were unrecognized in 

 Amphiura. The homology of the marginals is in doubt, and it is prob- 

 ably not represented in Amphiura. Possibly the marginals are homol- 

 ogous with the (adambulacrals) laterals. 



Cambridge, January, 1888. 



