696 BULLETIN 82, UNITED STATES NATIONAL MUSEUM. 



On the 2()tli of that month Lo Bianco, dredging off Posilipo at a depth of 

 about 30 meters, took only three specimens, all severely mutilated and dying with 

 the arms almost devoid of pinnules. On the reef at Gajola also Lo Bianco was 

 only able to find a very few specimens. 



Lo Bianco states that he can not explain satisfactorily the manner in which 

 the cinders caused the death of these crinoids. He suggests that the animals, 

 gradually becoming covered by the falling cinders, at last found themselves in 

 an unfavorable environment, and that weakness caused by hunger, combined with 

 the general disturbance caused by the stratum of cinders, induced autotomy, which, 

 becoming more and more extensive, resulted finally in death. 



He was led to this conclusion from ha\'ing observed that this species, which 

 lives A^ery well in the tanks of the aquarium during the cold season, perishes 

 through gradual progre.ssive fragmentation when the temperature of the water 

 becomes lower or higher than normal. 



Antedon mediterTanea showed the effect of the rain of cinders at least a week 

 later than the echinoids. 



Specimens of Leptometra fhalangimn. dredged on the 7th of May at a depth 

 of about 400 meters, between Capri and Ischia, were in the very best condition; 

 but the cinders which fell here were very few. 



EXPERIMENTAL INVESTIGATION OF THE DORSAL NERVOUS SYSTEM. 



In order to convince himself of the nervous nature of the axial cords of the 

 arms and to ascertain the intercorrelation between the nerves of the different arms 

 Dr. W. B. Carpenter carried out a number of experiments, using as his subject 

 Antedon hifda. 



Experimoit 1. — -Taking a large and vigorous specimen he turned the entire 

 visceral mass out of the calyx. 



On being replaced in water it executed the usual swimming movements as 

 perfectly as the entire animal would have previously done. 



Experiment 2. — From a second specimen, which he took out oi the water in 

 the act of swimming, he removed the entire centrodorsal with its contents and 

 appendages, leaving every other part as it was. 



On replacing the animal in water all the arms were rigidly straightened 

 out, apparently by the action of the dorsal elastic ligaments which the muscles 

 were now powerless to antagonize. 



Experiment 3. — In another lively specimen he divided the soft parts of one 

 of the arms down to the calcareous segment. 



On replacing the animal in water all the arms worked as usual, without the 

 slightest disturbance of regularity. 



Experiment I).- — He sevei'ed the dorsal nerve cord in one arm by the use of 

 nitric acid. 



On renlacing the animal in water that arm remained rieidlv .straightened out, 

 while all the other arms worked as usual. 



Experiment 5. — The entire visceral mass was removed from a specimen in 

 such a way as to leave nothing but the calyx with the central capsule and its 



