144 P. HERBERT CARPENTER. 
system only, and would not give this name to any vessel con- 
nected with either end of the ovoid gland. 
I do not regret my remark, however, as it has drawn from 
him a definite statement of his views; and if I interpret them 
aright, I am glad to find them more in accordance with those 
which I expressed in my previous note than I had any reason 
to expect. He says: 
‘* Je considére le canal du sable,! la glande et le canal madréporique chez le 
Spatangue comme respectivement homologues au canal glandulaire, a la glande 
ovoide et son conduit excréteur chez l’oursin, et que le canal du sable de ce 
dernier est représenté chez le spatangue par le canal onduleux qui accompagne 
’oesophage * plus le canal a épithélium cylindrique dont il était question tout 
a Vheure. Ces deux canaux ne représentent que les deux extremités du canal 
du sable dont la région moyenne aurait disparu et dont l’extrémité apicale 
aurait perdu les relations qu’elle a chez |’Oursin avec la plaque madréporique.” 
With the exception of the second half of the last sentence 
this is precisely the position which I took up in my previous 
note®. Our only point of difference appears to be the follow- 
ing one. The canal with columnar epithelium is described by 
Koehler, on the results of injection* as losing itself “ dans 
les lacunes du tissu conjonctif.”’ Teuscher> spoke of it as 
“Der Steincanal, welcher an seinem Cylinderepithel leicht 
kenntlich ist; and he supposed it, though erroneously so, as 
Koehler has shown, to be continuous with the tube which 
unites the organ of excretion with the oral blood vascular-ring, 
i.e. Koehler’s “ canal du sable.” 'Teuscher evidently assumed, 
though he nowhere demonstrated, that it opened to the exterior 
through the madreporite; but this connection is denied by 
Koehler,® though he does not support his statements by figuring 
any sections which show the gradual subdivision of this canal, 
as described by him. 
Like myself, however, he considers it as homologous with the 
dorsal end of the water-tube (canal du sable) of Echinus; 
1 This is coloured blue and lettered C, on pls. i—iii of Koehler’s memoir. 
2 C’ of Koehler’s figures. 
§ This Journal, vol. xxiii, pp. 607—609. 
4 * Zool. Anzeiger,’ 1885, p. 82. 
5 Loe. cit., p. 532. 
6 « Recherches,’ p. 99. 
