L. Agassiz on the Echinodermata. 441 



violacea possesses eyes, showing themselves as beautiful red points 

 on the under surface of the extremity of the five rays. 



I. The Asterim answer to the limits which Lamarck had assigned 

 to the genus of this name, established by Linnaeus in a more com- 

 prehensive view. What distinguishes them is their possessing a 

 single orifice of the intestinal canal surrounded by suckers but void 

 of teeth. On the dorsal surface we remark between the two posterior 

 rays a lamellate or rather a fibrous tubercle, which has been deno- 

 minated madreporiform. There are deep grooves from the mouth to 

 the extremity of the rays containing several series of pedicels. 



1. Asterias, Linn, and Ag. (Astropecten, Link. — Crenaster, Lloyd. 

 — Pentasterie, De Blain. in part. — Stellaria, Nardo, a name already 

 employed for a genus of plants.) Body starlike ; superior surface 

 tessellated ; rays flattened, edged with two series of large laminae 

 bearing small spines. 



A. aurantiaca, Linn. — A. bispinosa, Otto. — A. caleitrapa, Lam., and se- 

 veral new species. 



2. Ccel aster, Ag. — Differs from the preceding genus in having 

 the interior cavity circumscribed by laminae arranged like those of 

 the Echini, and at whose summits we observe a star of ambulacra. 

 This genus approaches therefore by its organization to the family of 

 the Crino'idea, while its form is that of the true Asteriee. I am only 

 acquainted with one fossil species, which is from the chalk. 



C. Coulon, Ag. 



3. Goniaster, Ag. (Scutasterie and Platasterie, De Bl.) — Body 

 pentagonal, bordered by a double series of laminae bearing small 

 spines ; upper surface nodose. 



G. reticulatus, Ag. (Asterias retic, Linn.) — G. equestris, Ag. (Ast. equ., 

 Linn.) — G.nodosus, Ag. (Ast. nod., ZzVm.) — G. tessellatus, Ag. (Ast. tessel,, 

 Lam.) I think this is also the place for several imperfectly known fossil 

 species, as G. porosus, Ag. — G. Couloni, Ag. — Asterias quinqueloba, Goldf. 

 — A.jurensis, Munst. — Thelaminse described under the names of Ast. scu- 

 tata, stellifera, and tabulate/, are probably only the calycinal laminae of some 

 unknown Crino'idea, if they do not belong to this genus. 



4. Ophidiaster, Ag. — Body starlike, finely tessellated on its whole 

 surface, inferior grooves very narrow. 



O. ophidianus, Ag. (Ast. ophid., Lain.) 



5. Linkia, Nardo (Cribella, Ag., MSS.) — Body starlike, rays 

 tuberculous and elongated ; epidermis porous in the intervals. 



L. variolata, N. (Ast. variol., Lam.) — L. typus, N. — L. Franciscus, N. 

 The species described by Goldfuss under the names of Asterias arenicola 

 and obtusa, appear to form a separate genus which might be called Pleur aster. 

 I am however not sufficiently acquainted with them to decide. 



