FOREIGN JURASSIC STOMECHINI. 223 



Stomechinus Orbignyantjs, Coiteau. Syn. Echinus Orhignyanus, Cotteau. Etudes sur 



les Ecliinides Fossiles, pi. 21, figs. 8—1:3. 



Test hemispherical, depressed ; circumference circular ; ambulacra with two marginal 

 rows of tubercles, and a naked zone between : inter-ambulacra with six rows of tubercles 

 at the equator, diminishing to two rows above ; base concave ; mouth opening wide, half 

 the diameter of the test ; peristome pentagonal, deeply notched. 



Dimensions. — Height, six tenths of an inch ; transverse "diameter, one inch and one 

 twentieth. 



Formation. — " Calcaires marneux et lithographiques de Commissey Corallien etage." 

 Cotteau. 



Collection. — ]\I. Rathier. Very rare. 



Stomechinus excavatus, Golclfuss. Syn. Echinus excavatus, Goldfuss. Petrefacta. 



Germanise, tabl. 40, fig. 12. 



Test hemispherical, depressed, sub-pentagonal ; ambulacra with two marginal rows of 

 close-set tubercles, smaller than those of the other areas ; inter-ambulacra with two rows 

 of primary tubercles on the sides, and four other secondary rows at the base. 



Dimensions. — Height, eleven twentieths of an inch ; transverse diameter, one inch. 



Formation. — " Eindet sich in den obersten Schichten des Jurakalkes bei Regensburg 

 und in Schwaben." Goldfuss. 



Collection.— M\mvck Museum. Very rare. 



Stomechinus serialis, Agassiz. Syn. Echinus serialis, Agassiz. Echinod. Foss. Suisse, 



II, tabl. 22, figs. 10—12. 



Test circular, much depressed ; ambulacra with two regular rows of tubercles ; pori- 

 ferous zones very narrow ; inter-ambulacra with six rows of tubercles at the circumference, 

 diminishing to two rows above ; mouth opening very large ; peristome decagonal, with 

 obtuse notches. 



