NARRATn'E oi' Bahama Expeihtion. 133 



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

 but even 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 \vith this fluid 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 onl}- profanity that I heard during the 

 trip w'as wrung from some of our best young men by the 

 unbearable pain inflicted by the spines of D. setositin. 



When the animal w^as undisturbed, resting on the bottom, 

 the long black spines w'ere symmetrically arranged radiating 

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

 w'ould 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 writer experimented by placing his 

 finger as lightly 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 b\- compressing the bundle of 

 longitudinal fibres. 



Echiiwnicira siibaiigular/s Desml. was common on the nuul- 

 flats. together with a very large species, probabh- JIipf>onoc 

 Cicidcnta A. Ag., with short white spines and a much larger 

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

 Toxopiictis/cs z'aric^-ahis A. Ag. is also found here, but all of 

 the specimens were of the variety having thick reddish-browm 

 spines, and would have been considered a distinct species from 

 those collected at ]5ahia Honda w^ere it not for the emphasis 

 laid by Agassiz on the extreme variability of this urchin. 

 Echiii'.vitlius. rosacciis Gray was found in limited numbers, and 



