401 



ORDER II. 



APODA. 



Our second order of the Echinodermata, or the Apoda. comprises 

 but a small number of animals closely related to the Holotlmrise, but 

 which want the vesicular feet of the preceding order. Their body is 

 invested with a coriaceous unarmed skin. Several points of their 

 internal structure are not well understood. In 



MoLPADiA, Cuv., 



As in Holothuria, we find a coriaceous body forming a thick cylin- 

 der open at both ends, and a tolerably similar internal organization; 

 but independently of the want of feet, the mouth is destitute of ten- 

 tacula, and is provided with an apparatus of bony parts, but less 

 complicated than that of the Echini. 



M. holothurioides, Cuv. The only species that I know in the 

 Atlantic Ocean. The anal extremity terminates in a point. 



MiNYAS, Cuv., 



Where the body is also destitute of feet and open at both extremities; 

 but its form is that of a spheroid depressed at the poles, and furrowed 

 like a melon. I can find no armature about the mouth. 



M. cijanea, Cuv., Regn., Anim., IV, pi. xv, f. 8*. A beau- 

 tiful species of a deep-blue colour that inhabits the Atlantic 

 ocean *. 



Priapulus, Lam., 

 Where the body is cylindrical and transversely marked with deep 

 annular rugae, terminated anteriorly by an elliptical mass slightly 

 wrinkled longitvidinally, perforated by the mouth, and posteriorly by 

 the annus, from which issues a thick bundle of filaments which may 

 be organs of generation. The interior of the mouth is provided with 

 a great number of extremely sharp and horny teeth arranged in quin- 

 cunx, and directed backwards; the intestine proceeds in a straight line 

 from the mouth to the anus. The muscular system resembles that of 

 the Holothurise. 



P. vulgaris; Holothuria priapus. Mull., Zool. Dan., XCVI, 

 1. It is from two to three inches in length, inhabits northera 

 seas, and is the only species known. 



LlTHODERMlS, CvV., 



Where the body is oval and compressed posteriorly; its surface has 

 the appearance of b^-ing covered with a layer of stony granules, which 

 form an extremely indurated crust. The mouth is surrounded with 



* Taken to France by M. Peron, 



