63 



CHAPTER VII. 



ECHINODERMATA.* 



It is beautiful to observe by what gentle steps the 

 student of Mature is able to ascend, from the con- 

 templation of one form of animal life to another 

 more elevated in the scale of creation. ^Ye have 

 learned, in the preceding chapter, that many tribes of 

 the Polypes secrete calcareous matter in large quan- 

 tities, and thus construct for themselves a solid 

 framework, Nvhich sustains the living mass. Let us, 

 for a moment, suppose a Polype supported upon a 

 long stem, capable of strengthening its pedicle, its 

 body, the tentacula around its mouth, and all the 

 appendages belonging to the animal, with solid pieces 

 of definite form, such pieces being connected together 

 by the soft parts and surrounded on all sides with 

 living flesh, w^ould thus form an internal skeleton, 

 giving strength and support to the entire fabric, and 

 at the same time allowing it to bend in every direc- 

 tion. A Polype so constituted w^ould, wdien dried, 

 present an appearance resembling that depicted in 

 the annexed figure (Fig. 44, 7). The creature repre- 

 sented, however, is not a Polype, but an 



Encrinite,! one of the lowest of the class of Star- 

 fishes. In its habits of life an Encrinite, thus con- 

 structed, closely resembles the more highly-organized 

 Anthozoa. Fixed by its jointed stem upon the sur- 

 face of the rock, it curves its pedicle from side to 

 side in search of food, which with its flower-like 

 arms, it seizes and conveys into its mouth. These 

 Encrinites are, in modern times, the scarcest pro- 

 ductions of the ocean. A species similar to that in 

 om- engraving exists in the West Indian seas ; and 



* ix^'^o^' ecliinos, a hedgeJiog ; Sepjia, derma, shin. 

 t *ei/, en, in ; Kpivov, lainon, a lily. 



