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Isomelra vwijxiKt Morlcnsen; development described, the present author, 

 1920. 



Compsomelra scrrnlit (A. II. (Hark); part of the development described, 

 the present author, 1920. 



Tropiomelra carinala (Lamarck); reared through metamorphosis, the pre- 

 sent author (1916), 1920. 



Notocrinus uirilis Morlensen: larva described, the present author, 1920. 



In the present memoir are given, besides additional observations on 

 the development of the following species: Stronyylocentrotus franciscanus, 

 Lylechinus ixiriei/dtns, Tripni-uslt-s rsculcntus and Peronella Lcsueuri, obser- 

 vations on the development and the larval form of the following species, 

 which were hitherto entirely unknown as regards their development: 

 I'hyllacanthus panns/tinus Woods; cleavage and gaslrulation only. 

 Eucidaris Thouarsi (Yal.): reared to beginning pluteus. 

 Arbacia stellata (Blv.); pelagic larva identified. 

 Diadema antillaium Phil. ; reared to first larval stage. 

 Aslropyga pulinnatti (Lamk.); reared to first larval stage; pelagic larva 



identified. 



Tripneustes ijratilla (Linn.); reared to first larval stage. 

 Lylechinus anamesus II. L. Clark; reared to full larval shape. 

 Lylechinus pictus (Verrill); reared to first larval stage; fully formed pelagic 



larva identified. 



Lylechinus panamensis Mrtsn.; reared to first larval stage. 

 Lylechinus uerruculalns (Ltk.); reared to first larval stage. 

 Toxopneustes pileolus (Lamk.); reared to first larval stage. 

 Toxopneustes roseus (A. Ag.); reared to first larval stage; pelagic larva 



of more advanced stage identified (not beyond doubt). 

 Pseudocentrotus ili'i>ressus; reared to first larval stage. 

 Strongylocentrotus pulchcrrinnis (A. Ag.); reared to nearly full larval shape. 

 Temnopleurus lomiinnlicus (Klein); reared U> nearly full larval shape. 

 Temnotrema sculpla A. Ag. ; reared to nearly full larval shape. 

 Mespilia globulus (Linn.); reared to full larval shape. 

 Evechinus chloroticus (Yal.): reared to full larval shape. 

 Heliocidaris Inbcrculalus (Lamk.); reared to full larval shape. 

 Heliocidaris erylhroyrammn (Val.): reared through metamorphosis. 

 Echinomdra lucunler (Linn.): reared through metamorphosis. 

 Echinomi'tni oblonga (Blv.); reared to nearly full larval shape. 

 Echinometra Mathxi (Blv.); reared to first larval stage. 

 Echinomdra van Brunli A. Ag. : reared to first larval stage. 

 Colobocenlrolus <tlr<tliis (Linn.); reared to nearly lull larval shape. 



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