REPORT ON THE CRINOIDEA. 407 



There is strong reason to believe that the " ovoid ghmd " of an Urchin or Starfish 

 does not communicate with the exterior through the madreporite as described by 

 Perrier, while there can now be no question respecting its direct connection with what 

 has been generally described as the oral blood-vastailar ring of these ty])es. Koehler's 

 observations^ have demonstrated this connection in the Urchins, although it was 

 categorically denied l)y Perrier.' It thus seems probable that although the " ovoid 

 gland " can no longer be described as a heart or even as a plexus of interlacing vessels, 

 yet that it is a glandular structure interpolated in the blood-vascular sj^stem, and 

 possibly one of the factories of the well known respiratory pigment of the Echinodenns. 

 The following remarks by Welldon ^ are noteworthy in connection with this suliject : — 

 "It is not too much to say that in every group of Invertebrates in which the vascular 

 system has been at all carefully investigated, glandular appendages to the vessels have 

 been found, which can, from their anatomical relations, have no other function than that 



of elaborating some of the constituents of the blood In Echinoderms, the 



abundance of glandular cells in the cardiac plexus is probably a principal cause of 

 the whole organ being regarded by many observers as an excretory apparatus." 



NOTE G. 



(Page 119.) 



The Nervous System of the Crinoidea. 



Since the section on the nervous system was written {ante, pp. 111-127), the subject 

 has been still further discussed by various morphologists, most of whom, I am glad to 

 say, have adopted the \aews advanced therein, and have strengthened them very 

 considerably. As in so many other cases, it appears that the doctrine of the nervous 

 nature of the axial cords in the skeleton of a Crinoid is not of such recent growth as has 

 been supposed. For the foUomng passage from von Schlotheim * would seem to show 

 that a nervous function was attributed to the contents of the central canal of the skeleton 

 more than sixty years ago : — " Da die Eneriniten aber sammtbch mit einer durch aUe 

 Zweige laufenden Nervenrohre versehen sind, und das Thier wenn es gleich mit der 

 Wurzel angewachsen zu sein scheint, doch mit alien seinen festen Theilen beweglich 

 bleibt, so gehort er ofFenbar nicht zu der Coralleuarten, und*macht nur ein merk-wiir- 

 diges Verbindungsgiied zwischen der Classe der Crustaceen uud der Zoophyten aus." 



A general, and, on the whole, tolerably accurate account of the morphology of living 

 Crinoids was published by Weinberg ^ in the course of last year (1883). It is principally 



1 Op. cit, p. 65, pi. 3, fig. 13. 2 Archives de Zool. expdr., vol. iv., 1875, p. 613. 



' On the Head-Kidney of Bdellostoma, with a suggestion as to the origin of the Suprarenal Bodies, Quart. Joum. 

 Micr. Sci., vol. xxiv., 1884, N. S., pp. 180, 181. 



* Die Petrefaetenkunde, Gotha, 1820, p. 327. 



5 Die Morphologie der lebenden Crinoideen mit Beziehung auf die Form Antedon rosacea, Linck, Der Naturhis- 

 toriker, 5 Jahrg. Jlarz-Juni Heft, 1883, pp. 266-307. 



