Narrative of Bahama Expedition, 133 



glass, they are capable of piercing not only the human cuticle, 

 but ev^en strong leather shoes, a fact several times demon- 

 strated by our collectors while working in the shallows. The 

 wound is quite severe, and as painful as a wasp's sting. The 

 tip of the spine is usually broken off in the wound, and a dark 

 crimson or purple fluid is injected. The spines and test of the 

 animal seem covered with this tiuid in life, giving a bloody 

 appearance. Whether this secretion is poisonous or not, the 

 wound is so painful as to suggest it. Several of our party 

 suffered severely from this cause, especially while trying to 

 get hold on the under side of coral heads, when the hand 

 would often come in contact with scores of these long, cruel 

 spines. Almost the only profanitv that I heard during the 

 trip was wrung from some of our best young men by the 

 unbearable pain inflicted by the spines of D. setosinn. 



When the animal was undisturbed, resting on the bottom, 

 the long black spines were symmetrically arranged radiating 

 in all directions. Upon being touched, the points of the spines 

 would converge toward the disturbing object. It seemed to 

 several of us that the urchin had the power of imparting a true 

 thrust to the spines. The waiter experimented by placing his 

 finger as lighth' as possible against the tip of a spine, and 

 received a sting like that of a hornet. At the base of each 

 .spine is a considerable mass of muscle fibres, but a somewhat 

 hasty examination does not reveal any circular muscles which 

 might give a thrust to the spine by compressing the bundle of 

 longitudinal fibres. 



Echinonictra siibaiigularis Desml. was common on the mud- 

 fiats, together with a very large species, probablv Ilipponoc 

 c^culcnta A. Ag.. with short white spines and a much larger 

 test than is found in specimens of this species in the Bahamas. 

 Toxopnciistes van'c^-atiis A. Ag. is also found here, but all of 

 the specimens were of the varietv having thick reddish-brown 

 spines, and would have been considered a distinct species from 

 those collected at Bahia Honda were it not for the emphasis 

 laid by Agassiz on the extreme variabilitv of this urchin. 

 Echiii'.aitliiii rosacciis Grav was found in limited numbers, and 



