50 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I44 



fig. a), not broadened in some specimens, slightly broadened in others, 

 with many pore pairs arranged in three series in each half-ambula- 

 crum, in a large specimen (84 mm. long) approximately 18 pore 

 pairs in each outer and inner series, 1 1 in each median series ; pore 

 pairs extending almost to peristome; no buccal pores. 



Tuberculation. — Tubercles on adoral surface larger than those on 

 adapical surface. 



Occurrence. — Jurassic (Bathonian-Callovian) of France, Switzer- 

 land, England, Madagascar, and British Somaliland. 



Location of type specimen. — Unknown. 



Remarks. — There has been considerable controversy over whether 

 or not P. depressus and P. michelini Cotteau are synonyms. Currie 

 (1925, pp. 66-67) gives a thorough discussion of this problem and 

 concludes that although one may be a variety of the other, they 

 should be considered conspecific. 



Lambert and Thiery (1921, p. 356) considered P. fiingiformis 

 (Agassiz, L., 1840a, p. 5) the type species of Mepygurus, and the 

 senior synonym of P. michelini. P. fungiformis, however, is a 

 nomen nudum. 



Subgenus PYGUROPSIS De Loriol 



Pyguropsis De Loriol, 1902. Notes pour servir a I'etude des echinodermes, 

 vol. 10, p. 32. Type species by original designation, Pygtirus noetlingi 

 De Loriol. 



Description. — The type species of this subgenus differs from all 

 the other species of Pygurus in having a thicker test with steeper 

 sides. 



Remarks. — Mortensen (1948, p. 165) further distinguished this 

 subgenus from Pygurus because of its smaller test, broader petals, 

 and periproct on the posterior edge of the test. However, although 

 the holotype is a small specimen, there is no way of knowing that 

 it was an adult since only one specimen is known of this species. 

 The petals are no broader than those in Pygurus {Mepygurus) 

 depressus, and the periproct is in the same position as in Pygurus 

 lampas. 



Range and distribution. — Cretaceous (Cenomanian) of Lebanon. 

 Only one species is known. Fourtau's Pyguropsis lorioli is a Bothryo- 

 pneustes as discussed on page 40. 



