51 



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

 fully formed larva of a true Sirongylocenlrotus-species. 



Concerning llie four anterior epaulets 1 may point out that it cannot 

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

 separated off from the vibralile band or not; in the latter case they will 

 be no true epaulets. l)ul only the band along the vibratile lobes. 



Siromjylorcnlrotus franciscuims, together with the other Californian 

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

 studies, especially by Loeb. In spite of this the larvai 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 larvse 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') the important information about the larva of Slron- 

 gylocentroius piirpiiratus that in its first stage it agrees closely with the 

 larva of S. drobachiensis and pidchenimus in having a long, clubshaped 

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

 than in franciscanii^, 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 (K^lein). 



Pl.X, Fig. 0. PI. XII, Fig. 6. 



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 that 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 I^luteus-shape 

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



V) -1. Locb, \V. (). R. King & .A. R. Moore. Cber Doininanzersclicinungen bei den 

 liybriden I'liitcus des Seeigels. .^rcii. f. Entw. Mechanik. Bd. 2'J. 1910. p. 354— .562. Taf. 

 XI— XII. 



J. Loeb. (*ber die Natur dcr Bastardlarve zwischen deni Echinodermenei (Strongylo- 

 c-entrotus franciscanus) und Molliisl<ensamen ((^hlorostonia funebrale). .'Vrcli. f. l-jitw. Mech. 

 Bd. 26. 1908. p. 476— 82. 13 figs. 



J. Loeb. Weitere Vcrsuchc iiber helerogene Hybridisation bei Ecliinodernien. .Vrcli. 

 f. d. ges. Phy.siologie. Bd. 104. 1904. p. ;^25— 50. 



J. Locb. Die cheniische Entwici<liingscrregung des tierischen Eies. 1009. (On p. 7, Fig. 

 17 is represented a young Pluteus of SIrongyloc. purpiiraliis). 



A. L. Hagedoorn. On tlie purely motherly character of tlie Hybrids produced from the 

 eggs of Slrongylocenlrolus. Arch. f. EnLw. Mechanik. 27. 1909. p. 1 — 20. 



7* 



