ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 901 



given off to the ventral integument of the body, where they are lost 

 in a fine nervous plexus. Luclwig's view of the glandular character 

 of the tentacles appears to be incorrect. They have 3-4 sensory hairs 

 and a centrally-placed slowly-moving flagellum. From these observa- 

 tions it would follow that the tentacular papillae are complicated 

 sensory organs 



Nervous System of Antedon rosaceus.* — This paper of Prof. A. 

 Milnes Marshall is of especial interest after the recent communica- 

 tions I of Dr. Carpenter and Dr. Herbert Carpenter. After a short 

 account of the general anatomy o{ Antedon, tind an historical sketch of 

 what has been done with regard to its anatomy and physiology, the 

 author passes to an account of his own experimental investigations. 

 The normal position of A. rosaceus is fixed ; when it swims about it 

 does so by strongly flexing the proximal half, and then extending the 

 whole arm, tlie distal half of which is thrown out somewhat like a 

 whip-lash or the line of a fly-rod. Irritation of the oral pinnules, 

 however slight, causes them to be firmly fixed over the disk ; if an 

 Antedon be detached and placed with its oral surface downwards it 

 will right itself almost at once. If an arm be cut off it will retain its 

 vitality for many hours, and at first exhibit strong movements of flexion. 



The first series of experiments were made on the Effects of 

 Removal of the Visceral Mass. A large and vigorous specimen after 

 eviscoration swam about the tank actively, and, after a period of rest, 

 again began spontaneously to move about; this experiment is the 

 same as one of Dr. Carj)enter's and proves that the co-ordinating 

 mechanism which regulates the complex swimming movements of the 

 arm is entirely without the visceral mass. The destruction of the 

 direct connection between the sub-epithelial bands of the several arms 

 renders it doubtful whether these bands have any regulating influence. 

 Another experiment showed that the nervous connection but ween the 

 sensory influence of any one of the arms or pinnules and the 

 muscular system is outside the visceral mass. A third experiment 

 gave evidence tliat the co-ordinating centre of the complex muscular 

 movements is situated in the calyx. 



TJie Poioer of Regeneration of Eviscerated Specimens has been 

 observed in a series of specimens, on which the author promises 

 fuller details ; it is already clear that the pow^er of regeneration in 

 Antedon exceeds even that which is well known to be possessed by 

 Holothurians. 



The Functions of the Central Capsule were seen by experiment to 

 be such that irritation causes strong flexion of the arms, and there is 

 clearly a direct physiological connection between the capsule, and 

 the muscles of the arm ; and it is further clear that the sub- epithelial 

 bands form no part of the central mechanism. Removal of the central 

 capsule destroys the co-ordinating mechanism between the arms. 



The Axial Cords were found to be the means of communication 

 between the distal end of the arm and the motor mechanism ; in other 



• Quart. Journ. Micr. Sci., xxiv. (1884) pp. 507-48 (1 pi.), 

 t Bee this Journal, ante, p. 501. 



