136 On the Morj^hology and Classification of the Saleniid^e. 



basals. Eadial plates large, with the pore in the adoral edge ; 

 one plate may or may not enter the periproctal ring. Peri- 

 proct large, with a ])]ated membrane pierced by the anal 

 opening. Ambulacra narrow, witli two rows of primary 

 tubercles ; plates all simple primaries ; crowding rare near the 

 peristome ; when it occurs there are demi-plates. Interradia 

 with large primaries. Peristome with cuts for the external 

 branchia;, with a membrane plated or not. Perignatliic girdle 

 with broad ridges and slender ununited processes ; jaws with 

 the opening of the pyramid unarched ; teeth with a keel. 

 Spines of primaries long, slender, variable in ornamentation ; 

 small spines club-, wedge-shaped, and flat, Spheeridia exist. 



Fossil : Cretaceous, England, Europe, Asia, North Africa ; 

 Eocene, Europe, Asia; Miocene, Australia. 



Pecent : Caribbean Sea, both of the great oceans, Japanese 

 Sea. Depth from 60 to 1700 fathoms. 



It will have been remarked that nothing is said in this 

 diagnosis about ornamentation of the apical plates, or about the 

 crenulation and condition, whether smooth or not, of the mame- 

 lons of the primary tubercles. The ornamentation is that of the 

 family, and the perforation or non-perforation of the tubercles, 

 of all which are crenulated, is not of generic importance when 

 the subgenus Heterosalenia is considered. The imperforate 

 condition is typical of the true species of Salenia ; and the only 

 distinction between Cotteau^s Heterosalenia and these is a per- 

 forate condition of the primaries in the last-named genus, or 

 rather doubtful subgenus, which has but one species in the 

 Hippurite Chalk of Martigues. 



The forms which have been considered in this communi- 

 cation evidently belong to a family which is separable from 

 the Cidaridffi on the one hand, and the Diadematidaj, Arba- 

 ciidffi, Triplechinidas, and all other regular Echinoidea on 

 the other. 



Family Saleniidse. 



Pegular endocyclic gnathostoraes, with a persistent dorso- 

 central plate. A periproct posterior, directly or partly to the 

 right of the dorso-central plate, with a plated membrane, 

 which gives passage to an anal aperture. Ambulacral plates 

 either primaries or compound primaries. Perignathic girdle 

 with ridges and processes. Branchiai external. 



Genus Acrosalenia, Agass., 1840, amended. 

 Syn. Pseudosaleniay Colt. 



