ANCHORS OF SYNAPTAI — WHEELS OF CHIRODOTA. 



567 



form shown at a, Fig. 294 ; and each of these carries the curious 

 Anchor-like appendage, c, which is articulated to it by the notched 

 piece at the foot, in the manner shown (in side view) at b. The 

 Anchor- like appendages project from the surface of the skin, and 



d? 



Calcareous Skeleton of Synapta : — a, plate imbedded in Skin ; 

 e, the same, with, its anchor-like spine attached ; c, anchor-like 

 spine separated. 



Fig. 295. 



may be considered as representing the spines of Echinida. — Nearly 

 allied to the Synapta is the Chirodota, the integument of which is 

 entirely destitute of 'anchors,' but is furnished with very remark- 

 able Wheel-like plates ; those represented in Fig. 295 are found 

 in the skin of Chiro- 

 dota violacea, a spe- 

 cies inhabiting the 

 Mediterranean. These 

 Wheels are objects 

 of singular beauty 

 and delicacy, being 

 especially remarkable 

 for the very minute 

 notching (scarcely to 

 be discerned in the 

 figures without the 

 aid of a magnify- 

 ing-glass) which is 

 traceable round the 

 inner margin of their 



'tires.' — There can be scarcely any reasonable doubt that every 

 member of this Order has some kind of Calcareous Skeleton, 

 disposed in a manner conformable to the examples now cited ; and 

 it would be very valuable to determine how far the marked pecu- 

 liarities by which they are respectively distinguished, are charac- 

 teristic of Genera and Species. The plates may be obtained sepa- 

 rately by the usual method of treating the Skin with a solution of 



"Wheel-like plates from Skin of Chirodota 

 violacea. 



