14 Trans. Acad. Sci. of iSt. Louis. 



1897. Echinocystis pomum. Gregory, Quart. Journ. Geol. 



Soc. London, vol. 53, pt. 1, p. 124, pi. 7, fig. 4. 

 1899. Echinocystis pomum. Sollas, Quart. Journ. Geol. 



Soc. London, vol. 55, pt. 4, p. 707, figs. 12-14. 

 A row of minute tubercles border the ambulacra on the 

 outer margin, and a double row of even smaller tubercles runs 

 along each side of the middle line. Porepairs lie in an oval 

 depression. 



Geological formation and locality: Leintwardine Flags, 

 Lower Ludlow, near Leintwardine, Shropshire. 



B. BOTHRIOCIDAROIDA Zittel 1879.* 



Test regular, spherical. Two columns of plates in the 

 ambulacral area and a single column in each interambulacral 

 area. Plates do not imbricate. Periproct in the apical system. 



I. BoTHRiociDARiDAE Schmidt 1874. t 



Body round, regular. Anal within the apical disk. 

 Apical disk composed of a ring of five large and five small 

 plates. Two pores in each ambulacral plate. Mouth sur- 

 rounded by ten perforated plates in front of which are 

 three-cornered small plates. 



a. BoTHRiociDARis Eichwald 1860. t 



Body round, anus within the apical system, mouth 

 opposite. 



Plates not flexible. Apical system composed of five large 

 and five small plates, within which is the anus closed by six 

 or eight linear or oval plates, each of which has a spine on 

 the end. Two pores in each of the larger plates, while the 

 smaller plates are imperforate. 



* Handbuch der Palaeontologie Bd. 1, p. 480. 



t Mem. Acad. Imp. St. Petersburg, (7) vol. 21, no. 11, p. 36. 



X Lethaea Rossica, p. 654. 



