FOREIGN JURASSIC STOMECHINI. 223 



Stomechinijs Orbignyanus, Cotteau. Syn. Echinus Orbignyanus, Cotteau. Etudes sur 



les Echinides Fossiles, pi. 21, figs. 8 — 13. 



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. — M. Rathier. Very rare. 



Stomechinus excavatus, Goldfuss. 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. — Munich 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. 



