51 



it worth while giving this figure, since otherwise no figure exists of a 

 fully formed larva of a true Strongylocentrotus-spedes. 



Concerning the four anterior epaulets I may point out that it cannot 

 be decided from the single specimen in hand, whether they have been 

 separated off from the vibratile band or not; in I he latter case they will 

 be no true epaulets, but only the 'band along the vibratile lobes. 



Strongylocentrotus Irancixamus, together with the other California!! 

 species S. purpiirnlus, has been the object of a great many experimental 

 studies, especially by Loeb. In spite of this the larv;e of these two species 

 have not been described hitherto in any way adequately: only some out- 

 line figures have been given of the first larval stage for the sake of com- 

 parison with hybrid larva? of the two said species, while no informa- 

 tion at all is given of the later larval stages. But at least we may gather 

 from these papers 1 ) the important information about the larva of Slron- 

 yylocvntrotus purpiirdlus that in its first stage it agrees closely with the 

 larva of >S. drobachicnais and ])ulcherrinws in having a long, clubshapecl 

 body rod; there may be an indication of a recurrent rod, much smaller 

 than in franciscanus, and there is, accordingly, no basket-structure. 

 The species breeds during the winter season. I had therefore no opport- 

 unity myself of studying its development. 



Temnopleurus toreumaticus (Klein). 



PI. X. Fig. ti. PI. XII, Fit;, li. 



Fertilization of this species was undertaken at Misaki on June 25th 

 and again on the 29th, the first culture being unsuccessful. The eggs are 

 very small and transparent. The cleavage and the first developmental 

 processes go very rapidly, so thai already after about 12 hours the embryos 

 leave the egg-membrane in the shape of blastula>, and at the age of ca. 

 22 hours the embryos were found to have assumed the Pluteus-shape 

 (PI. XII, Fig. 6). A conspicuous feature of the young larva is the very 



M .1. Loch. \V. o. H. King & A. R. .Moon-. ('her Dominanzerscheinungen bei den 

 hybriden Plulcus des Seeigels. Arch. I'. Entw. Mechanik. Hd. 2'.i. I'.Hii. p. .'!.">! :;ii2. Till'. 

 XI XII. 



.1. Loch. I 'her die Niitur dor Bastardlarvc x.wischcn dcin F.chinodermenei (Slrongylo- 

 centrotus frandscanus) und Molluskcnsamon (C.hlorostoma funebralci. Arch. I. F.nl\v. Mfdi. 

 Bil. 26. 1908. p. 47682. 13 ligs. 



.1. Loeb. Weiterc Yersuchc iiher helorogene Hybridisation bei Kchinodermen. Arch. 

 I. d. ges. Physiologic. Bd. 10-1. HW-4. p. .T2.V .">n. 



J. Loeb. Die cheinisclic Kntwicklunnscrroiumn des licrischcn Ivies. 1!HiM. (On p. 7. Fin. 

 17 is represented a young Pluleus (il Slrnngyloi-. i>itri>nratiis). 



A. L. Hagedoorn. On [lie purely innlhcrly character <>l the Hybrids produced from tin- 

 eggs of Strongyloceutrotus. Arch. t. ICnlw. Mechaiiik. 27. IW.i. p. 1 2n. 



7* 



