610 P. HERBERT CARPENTER. 



are scattered about over the ventral surface of the disc, and 

 not collected into a single plate as in most Echinozoa. He 

 does not seem to believe in the connection of the central plexus 

 with the intervisceral blood-vessels, which has been described 

 by Ludwig and myself. For he says, " Les vaisseaux qui 

 paraissent en partir ne sont autre chose que les ramifications 

 de la glande, se terminant d'ordinaire par des renflements 

 ayant I'aspect de culs-de-sac. Ces ramifications courent au 

 milieu des innombrables trabecules du tissu conjonctif de la 

 cavite g^nerale, qui peuvent eux-memes parfois prendre I'appa- 

 rence de vaisseaux." In the early larva, the central plexus is 

 " un corps fusiforme plein, allant du cercle oral au p^doncule 

 dont il continue le cordon axial. Ce corps n'emet aucune 

 ramification : il ne saurait par consequent ^tre question a ce 

 moment d'appareil vasculaire. Le corps ovoide s'implante 

 chez la Comatule adulte sur I'un des planchers horizontaux 

 de I'organe cloisonn^." 



Professor Perrier does not definitely name the species which 

 has afibrded him material for his observations. But, as he 

 says that they have principally been made on young indivi- 

 duals, and on Pentacrinoid larvae, it is 'tolerably evident that 

 the common Ant. rosacea of the English Channel and the 

 Mediterranean has been the subject of his researches. I do 

 not know whether he has ever made preparations of Ant. 

 eschrichti, or of any species of Actinometra or Penta- 

 crinus. But unless he has done so, he appears to me to be 

 somewhat rash in denying the conclusions reached by other 

 workers who have had these opportunities, on the strength of 

 observations made on a single species. 



Some years ago Professor Perrier, who had worked by one 

 method only, was led not only to deny the existence of a 

 particular canal in the arms of Ant. rosacea, which had been 

 described by Dr. Carpenter, but also to predict that no one 

 else would find it. It has, however, been described by Greeff, 

 Teuscher, Ludwig, myself, and finally by Perrier himself; 

 and I cannot help suspecting, therefore, that he has been again 

 misled by the limited nature of his observations. The mere 



