380 p. HERBERT OAUPENTER. 



which are so abundant at the sides of the ambulacra, especially 

 in the pinnules. They occur in most, if not in all the species of 

 An ted on, but are not always equally visible, being, as a rule, 

 smaller and less darkly coloured in those from considerable 

 depths. Their nature has been a constant puzzle to me ever 

 since I began to make a special study of the Crinoids, eleven 

 years ago ; and any observations which would place their 

 nature beyond a doubt would be an immense relief to my 

 mind. Without desiring to express a decided opinion as yet, I 

 find some difficulty in accepting the theory that they are sym- 

 biotic algie, for reasons which will appear in the following pages. 

 I will first quote the description which is given by the Swiss 

 authors of these structures as they occur in Antedon 

 rosacea.^ 



/'Les spores amoeboides de ces Zooxanthelles imniigrent dans les larves, 

 pendant que celles-ci nagent encore dans la mer. M. Goette les a decrites 

 a cette epoque comme des cellules contractiles, colorees en jaune, munies de 

 noyaux, et ayant la forme de massues, dent le bout epaissi fait souvent encore 

 saillie au-dessus de I'epidernie, ou on les trouve constamment. Ces cellules 

 eutrent plus profondement dans les tissus, elles deviennent rondes, develop- 

 pent dans I'interieur des masses colorees, una ou deux, qui se divisent en 

 granules colles ensemble, Les paquets de granules reunis, out, suivant M. 

 Perrier, des queues tres longues et deliees, ce sont done de veritables zoo- 

 spores. Arrivees a cet etat, les Zooxanthelles ont encore le mouvement 

 amoeboide du a leur protoplasme incolore, et sont eutourees outre leur contour 

 propre, d'une sorte de capsule formee par les tissus." 



The structures which Vogt and Yung call amoeboid spores 

 are the pyriform oil-cells of Wyville Thomson,- who found 

 them in the larva, " immediately after escaping from the 

 vitelline membrane ;" and he further described how " the 

 surface is dotted over with the wider ends of large pyriform 

 lemon-coloured oil-cells immersed perpendicularly in the sar- 

 code." This fact appears to me to be a serious objection to 

 Vogt and Yung's theory that the lemon-coloured oil-cells are the 

 migrating amoeboid spores of symbiotic algse, which must lose 



1 Op. cit., p. 570. 



- "On the Embryogeny of Antedon rosaceus, Linck (Comatula 

 rosacea of Lamarck)," 'Phil. Trans.,' 1865, pp. 521, 522, pi. xxiv, fig. 5. 



