302 TWENTIETH REPORT ON THE STATE CABINET. 



EXPLANATION OF PLATE IX. 



Fig. 1. Pal^aster SH-aJFFERi. Ventral side, showing the ambulacral, 



adambulacral and marginal range of plates. 

 Fig. 2. Pal^aster matftina. Dorsal side. 

 Fig. 3. Pal^aster eucharis. Dorsal side. 

 Fig. 3^. Pal^aster eucqaris. Ventral side. 



Fig. 3 a. « " An illustration of a single ray, with the 



centre and bases of the other rays. The letters refer to the parts 

 as follows : 



a. Ambulacral plate ; 



p. The pore ; 



a, a. Adambulacral plate ; 



m. Marginal plate ; 



?, m. Terminal plate of the marginal series ; 



o. Oral plates, of which there are five pairs. 



Fig. 4. Paljeaster eucharis. A single ray deprived of its marginal 

 plates and flattened, showing a great length of the ambulacral 

 plates. In fig. 3, the concavity of the groove produces a shor- 

 tening of the plates of the ambulacral series. 



Fig. 5. Frotaster forbesi. View of the dorsal side in outline : natural 



size. 



Fig. 6. An enlargement of the lower side of a part of one ray, illustrating 

 the parts as follows : 

 0. Oral plate ; 

 p. The pore ; 

 a. Ambulacral plate ; 

 a, a. Adambulacral plate ; 



s. Spine from anterior end of adambulacral plate ; 

 d. The limit of the disc. 



Fig. 7. Eugaster logani. Specimen, natural size. 



Fig. 8. A portion of one ray enlarged, with references to the parts as 



follows : 



0, 0. The oral plates, of which there are five pairs, the apices 



of each being apparently joined by a suture to the basal 



portions ; 



a. Ambulacral plate ; 



a, a. Adambulacral plate ; 



p. Pore ; s. Spine ; 



d. Limit of circular disc. 

 22 



