GENERA AND GROUPS OF THE ECHOTOIDEA. 47 



G-enus Salenia, Gray, 1835, Proc. Zool. Soc. Lond. pt. 3, p. 58. 

 L. Agassiz, 1838, Monogr. d^Tlch. viv. (^ foss. livr. i. p. 6. 

 A. Agassiz, 1874, Revision of the JEchini, p. 258 ; 1883, Blahe, 

 Ech. p. 13. Duncan ^ Sladen, 1887, Ann. Sf Mag. Nat. 

 Hist. ser. 5, vol. xix. p. 132. (Amended.) 



Test small, subglobose or depressed. Apical system larger 

 than the peristome, more or less raised. The dorso-central plate 

 more or less geometrical, imperfect, and eroded at the right pos- 

 terior angle by the periproctal ring, in contact with all the basals. 

 Apical plates ornamented with radiating grooves and ridges. 

 Eadial plates large, with the pore in the adoral edge, one plate 

 may or may not enter the periproctal ring. Periproct large, with 

 a plated membrane pierced by the anal opening. 



Ambulacra narrow, with two rows of small primary tubercles 

 and granules ; plates all simple primaries, crowding rare near the 

 peristome. Pairs of pores in simple vertical series; tentacles 

 sub-homoiopodous. Interradia with large primaries. Tubercles 

 of both areas crenulate, or some plain, and imperforate. 



Peristome with cuts for the external branchiae, Vtdth a mem- 

 brane plated or not. Perignathic girdle with broad ridges and 

 slender ununited processes ; jaws with the foramen of the pyra- 

 mid small, unarched ; teeth with a keel. Spines of primaries 

 long, slender, variable in ornamentation ; small spines club-and 

 wedge-shaped and flat. Pedicellarise of the three kinds; epistroma 

 often much developed. Spheridia exist. 



Fossil. Cretaceous : England, Europe, Asia, North and "West 

 Africa. Eocene : Europe, Asia. Miocene : Australia. 



Recent. Caribbean Sea, both of the great Oceans, Japanese 

 Sea. Depth from 60 to 1700 fathoms. 



Subgenus Heterosalenia (genus), Cotteau, 1861, Pal. Frang., 

 Terr. Gret. p. 96, pi. 1022. Duncan ^ Sladen, 1887, Ann. 

 4" Mag. Nat. Hist. ser. 5, vol. xix. p. 132. 



The primary tubercles are perforated. 

 Fossil. Cretaceous : Europe. 



Division II. 

 In the second division of the genera of the Family the ambu- 

 lacral plates are compound at a short distance from the apical 

 system, and the pairs of pores are crowded near the peristome. 



