PREFACE. 



different, however, from the fossil spines of the same genus found 

 in the Tertiary formations of our shores. 



The succeeding Decades will illustrate as many different genera 

 as possible, and will deal first usually with species of some special 

 interest, and of which good figures do not exist, or are not easily 

 accessible. 



Frederick McCoy. 



16th September, 1883. 



[ 5] 



