ECHINUS. 121 



No specimen has fed on any animal suJjstance offered to it. 



I have been indebted to Dr Duguid, whose name is very familiar to 

 naturalists, for a number of fine Comatulaa from Orkney, where they are 

 not equally rare as in most other parts of Scotland. Some of them sur- 

 vived seven weeks. 



Plate XXX. 



Fig. 1. Comatula barbata. 



2. Prehensile organization, enlarged. 

 '6. Clasper and claw, enlarged. 

 4. Nipple, as rising from the disc. 



Echinus, the Sea Urchin.— Plates XXXI., XXXII., XXXIII. 



In the absence of facts sufficiently numerous and important for ex- 

 plaining the history of the lower animals, I shall substitute the accurate 

 representation of certain species not difiicult to be obtained, for I con- 

 sider it of some consequence that the reader may himself verify the truth 

 of Avhat is described. Nothing has suffered equal neglect, not so much 

 from inclination or oversight, perhaps, as from actual inability to accom- 

 plish that which was required. But, wherever practicable, this most 

 useful branch of illustration should never be omitted. It will sewe for 

 the solution of many doubts, the correction of fallacies, and the reple- 

 tion of inconvenient chasms. 



I am led to these remarks from finding the valuable observations of 

 reputable authors on the Echinus, either entirely void of the necessary 

 illustrations, or so deficient of resemblance to nature, that to recognize 

 them is impossible. I wish I could restrict the notice of such imper- 

 fections to the Echinus only. But it is to be regretted that they ex- 

 tend to the other subjects of the present section, especially the Holo- 

 thuria and the Stellerides, or Sea Stars. 



If such manifest imperfections be concomitant on endeavouring to 

 give the external aspect, which should be the easiest attained, how shall 



Q 



