170 FOREIGN OOLITIC HEMIPEDINAS. 



Hemipedina Nattheimense, Quenstedt. 



EcHiNOPSis Nattheimensis. Quenstedt, Handbuch der Petrefactenkunde, pi. 49, fig. 37. 



Test small, sub-pentagonal, depressed; ambulacra straight, one half the width of 

 row inter-ambulacra, with two rows of tubercles, nine to ten in each ; a row of granules 

 extends along the tract of the suture, and transverse branches pass in lateral directions 

 from the main line ; poriferous zones narrow, and strictly unigeminal ; inter-ambulacra 

 twice as wide as the ambulacra, with two rows of primary tubercles, nine in each 

 row, placed near the centre of the plates ; the bosses surrounded by distinct areolas, 

 complete circles of small granules encircle them ; near the base, some of the 

 granules attain the size of secondary tubercles, with perforated summits ; the tubercles of 

 both areas small and nearly of the same size, those of the inter-ambulacra a little larger 

 than those of the ambulacra ; apical disc small ; the ocular plates extend beyond the 

 line of the genitals, and are perforated near their centre ; vent round, surface of the disc 

 covered with small granulations ; mouth opening large and decagonal, lobes unequal. 



Dimensions. — Transverse diameter, eleven twentieths of an inch. 



Formation. — White Jura, i. Nattheim. 



Collections. — Professor Quenstedt, Tiibingen. 

 British Museum. 



Hemipedina BoucHAEDii, Wright, nov. sp. Mr. Davidson's MS., Plate III bis., figs. 1, 2, 3. 



Test large, depressed ; ambulacral areas with two rows of regular marginal tubercles, 

 extending without interruption from the peristome to the apical disc ; and separated by 

 a median row of granules, with transverse branches ; poriferous zones narrow, straight, 

 and strictly unigeminal ; inter-ambulacral areas three times the width of the ambulacral, 

 with ten rows of tubercles at the equator, each inter-ambulacral plate in this region having 

 five tubercles arranged on the same line ; areolas narrow, and surrounded by circles of 

 granules ; tubercles of both areas small and nearly of the same size ; spines long, slender ; 

 stem covered with well-marked longitudinal lines. 



Dimensions. — Transverse diameter, two inches and one quarter ; height unknown, a 

 the specimen is crushed. 



Formation. — Kimmeridge Clay, collected by M. Bouchard Chantereaux, from a cliff 

 near Boulogne-sur-Mer. Very rare. 



Collection. — M. Bouchard-Chantereaux, at Boulogne-sur-Mer. 



