118 Dr. P. H. Carpenter on some Points in 



radial abactinal plates of the young Brisinga eventually 

 become the odontophores ; and upon this supposition he 

 based a generalization concerning the whole of the Asterids. 

 As a matter of fact, however, he was merely repeating a 

 statement made some time previously, but never satisfactorily 

 proved ; while its accuracy has since been questioned by 

 Sladen *, who has also proved beyond all doubt that, what- 

 ever be the case in Brisinga^ Prof. Perrier is utterly at fault 

 with regard to the fate of the iuterradial abactinal plates in 

 other Starfishes. 



According to Prof. Perrier, it has been demonstrated by 

 himself, together with Koehler and Apostolides, that the 

 blood-vascular system of Urchins and Ophiurids communi- 

 cates directly with the exterior through the madreporite. 

 But I have pointed out elsewhere f that no valid proof of this 

 statement has ever been furnished to morphologists, except an 

 account of the results of injections. I may be peculiar, but I 

 do not believe in the injection method as a means of settling 

 intricate anatomical questions. Sometimes, as Ludwig has 

 shown in the case of Greeff and Hoffmann, it proves, or rather 

 appears to prove, far too much ; while in other cases it gives 

 altogether insufficient results. Some years ago, in conse- 

 quence of unsuccessful injections. Prof. Perrier was led to 

 deny the existence of what is generally known as the blood- 

 vascular ring of Echinus^ and of a vessel which had been sup- 

 posed to connect it with the so-called heart or ovoid gland %- 

 His friend Mons. Koehler, however, was able to demonstrate 

 the presence of these organs without difficulty ; and he con- 

 firmed the results of his injections by the section-method §. 

 But neither Koehler, Perrier, nor Apostolides has figured a 

 single section which shows how the ovoid gland of any Urchin 

 or Ophiurid communicates with the exterior ; though their 

 injections have caused them to speak of it as a demonstrated 

 truth about which there can be no doubt whatever ||. Lud- 

 wig's careful sections and dissections of the madreporite of a 

 Starfish, however, have led him to the conclusion, which his 



* Quart. Joum. Micr. Sci. n. s. vol. xxiv, pp. 39-41. 



t " Notes on Echinoderm Morphology. — No. VI./' Ibid. vol. xxiii. 

 pp. 697-609 ; No. IX. Ibid. Supplement, 1885, pp. 13-18 (of separate 

 copy). 



X " Sur I'Appareil ciroulatoire des Oursins," Comptes Kendus, Nov. 16, 

 1874 ; and " Recherches sur I'Appareil circulatoire des Oursins," Ai-ch. 

 de Zool. Exp. et Gen. t. iv. 1875, p. 613. 



§ ". Recherches sur les Echinides des Cotes de Provence," Ann. da 

 Mus. d'Hist. Nat. de Marseille, Zoologie, Mem. no. 3. pp. 65-70. 



II R. Koehler, " Quelques mots sur les relations du systeme circuUitoire 

 chez les Ecliiuides," Zool. Anzeiger, Jahrg. viii. 1885, p. 81. 



