REPORT ON THE CRINOIDEA. 17 



gave the name "five-chambered organ" or " quinquelocular organ" to the structure 

 which had been described by Midler as a single-chambered heart. For he found it " to 

 contain five chambers clustered like the carpels of an orange round a central axis ; " and 

 he described these chambers as being surrounded by a fibrillar envelope which he 

 regarded as nervous in character. Marshall ' again spoke of the cavity of the centro- 

 dorsal as lodging " a sac divided by vertical septa into five radial compartments, and 

 hence called the chambered organ " ; and he went on to explain how this is " surrounded 

 by a thick fibrillar investment known as the central capsule." Ludwig had previously 

 adopted the same terminology, 2 and, in fact, he was the first to speak of the " chambered 

 organ" without the numerical prefix, but he never used this expression to denote 

 anything else than the five chambers with their central axis inside the central capsule ; 

 while he further described and figured the radial axial canals, 3 the relations of which to 

 the coeliac canals of the rays and arms were subsequently pointed out by myself. 4 Their 

 connection with the body-cavity and their distinctness from the chambers of the so-called 

 heart were clearly recognised by Greeff, 5 both in his figures and in his descriptions ; 

 while I am not aware that Teuscher, G the only other recent original writer ou the subject 

 up to the time of Perrier and Jickeli, ever used the expression "chambered organ" at 

 all, though he often referred to the " Kammern des Gefasscentrums," and he recognised 

 the connection of the radial axial canals with the cceliac canals of the rays. 



Recently, however, Messrs. Vogt and Yung have figured not only the cavities with- 

 in the central capsule but also the radial axial canals, and the whole system of spaces 

 within the calcareous network occupying the centre of the radial pentagon, together with 

 some accidental cavities within the solid base of the centro-dorsal piece and in the radials 

 as " cavites dependantes de la cavite generale et constituant, dans leur ensemble, l'organe 

 dit cloisonne." 7 They say " Ce sont les espaces qu'on est convenu d'appeler, fort 

 improprement, l'organe cloisonne," and again " C'est la reunion de toutes ces excavations 

 internes, qui sont revetues de membranes, envoyant de cloisons transversales et dessinant 

 ainsi un systeme complique de lacunes cloisonnees, qui composent ce que les auteurs ont 

 appele l'organe cloisonne (Gekammertes Organ). C'est une denomination eminemment 

 impropre, vu que ce n'est pas un organe, mais une suite de cavites parcourues par l'organe 

 dorsal avec ses vaisseaux, et formant la continuation de la cavite generale du corps, du 

 coelome, qui entoure les intestins." 8 The statements contained in the first passage 



1 On the Nervous System of Antedon rosaceus, Quart. Joum. Micr. Sci., 1S84, vol. xxiv., N.S., p. 510. 



2 Beitrage zur Anatomie der Crinoideen, Zeitschr.f. wiss. Zool, 1877, Bd. xxviiL pp. 315-326. 



3 Ibid, p. 318. 



4 Trans. Linn. Soc. Lond. (Zool.), 1879, ser. 2, vol. ii. p. 78. 



6 Ueber das Herz der Crinoideen, Sitszungsb. d. Gesellsch. z. Beford. d. ges. Naturwiss. zu Marburg, 1876, No. 5, p. 93. 



6 Beitrage zur Anatomie der EchinoJermen : I. Coniatula mediterranea, Jenaische Zeitschr., 1876, Bd. iii. pp. 244- 

 260. 



7 Traite d' Anatomie comparee pratique, Livr. vii., 1886, p. 550, expl. of fig. 276. 



8 Ibid., p. 530. 



(zool. CHAX.L. EXP. PART LX. — 1888.) Ooo 3 



