101 



(4) The radial perihaemal canals and the outei ring-canal con- 

 necting them arise in Asterias pallida as blocks of mesenchyme which 

 subsequently become hollowed out; in Asterina gibbosa the ring-canal 

 and the basal portions of the radial canals arise in the manner descri- 

 bed by me 6 , but the distal portions of the radial canals arise by the 

 hollowing out of masses of mesenchyme having no connection with the 

 coelomic evaginations which give rise to the proximal portions of these 

 same canals. 



With regard to 1) I have to record that I have been utterly unable 

 to find any trace of such a secondary bending of the prae-oral lobe of 

 Asterina gibbosa to the right as Goto asserts. The original long axis 

 of the larva is indicated for a considerable part of the metamorphosis 

 by the direction of the larval intestine: — speaking generally the 

 long axis of the praeoral lobe is coincident in direction with the in- 

 testine — sometimes it is bent a little to the right — oftener on the 

 whole to the left. These flexures I believe to be due to the action of 

 preservatives, they are quite inconstant in amount and direction. We 

 may therefore dismiss the far fetched supposition which Goto has put 

 forward in order to conjure up a coincidence of planes of symmetry 

 where there is an obvious want of correspondence between them. — 

 Further let it be remarked that if in the case of Asterias pallida, the 

 aboral disc really does eventually come to occupy the posterior pole 

 of the larva so as to be perpendicular to both the frontal and sagittal 

 planes of the larva, this must be looked on as an isolated and exceptional 

 phenomenon, from which no conclusions can be drawn — since it is 

 opposed to all observations which have heretofore been made for the 

 development of Asterids, Ophiurids and Echinids. From Johannes 

 Müller down every observer has figured a marked obliquity of this 

 disc corresponding to the condition found in Asterina gibbosa. 



With regard to 2) Goto has apparently entirely failed to recog- 

 nize the real character of the changes which take place in the coelom. 

 Had he commenced his observations on Asterina gibbosa at an earlier 

 stage, he might have seen that exactly the same process takes place 

 on each side of the larva. A transverse septum is formed first in the 

 dorsal region, and is then prolonged ventrally until the posterior coelom 

 is entirely separated from the anterior. It must be remarked however 

 that Goto uses the term "posterior coelom" in a very misleading 



6 Goto apparently thinks that he has made a correction of my account of the 

 coelomic rudiments of the perihaemal spaces, by calling attention to the fact that 

 one of these rudiments originates from the axial sinus; he has apparently read my 

 paper carelessly or he would have seen that this fact was described (loc. cit. p. 360) 

 therein. 



