72 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I44 



anterior, tetrabasal, three or four genital pores; petals equal, flush. 

 Open or slightly closing distally, pores usually conjugate, all ambu- 

 lacral plates double pored ; periproct marginal, longitudinal, not 

 visible dorsally ; peristome anterior, higher than wide, pentagonal ; 

 bourrelets well developed, phyllodes broad, double pored, with pore 

 pairs in two series in each half -ambulacrum, inner or lower pore of 

 a pore pair usually smaller than other pore ; no buccal pores. 



Comparison zvith other genera. — Catapygus is very similar to 

 Phyllobrissus (see p. y6 for discussion of their similarities and 

 differences). It strongly resembles Pygaulus in shape, petal arrange- 

 ment, and position and shape of periproct, but differs in having a 

 pentagonal peristome and a well-developed floscelle with wide phyl- 

 lodes and well-developed bourrelets. 



Remarks. — As the phyllodes have been illustrated in very few 

 species of this genus, I include a drawing of the phyllodes of 

 Catopygus fenestratus Agassiz (text fig. 53) and Catopygus missis- 

 sippiensis Cooke (text fig. 54). 



Range and distribution. — Jurassic to Cretaceous (Kimmeridgian 

 to Senonian) of worldwide distribution. Lambert and Thiery (1921, 

 p. 353) list two post-Mesozoic species : Catopygus recens A. Agassiz, 

 and Catopygus cajonensis Kew. I have studied the type specimens 

 of both Kew's C. calif ornicus and C. cajonensis. They are both 

 internal molds, and from their shape and the anterior location of 

 their peristomes, they appear to be spatangolds and certainly not 

 Catopygus. Kew referred both species only provisionally to Catopy- 

 gus. Catopygus recens is a Studeria. 



DESCRIPTION OF TYPE SPECIES 



CATOPYGUS CARINATUS (Goldfuss) 



Plate 10, figures 5-8; text figures 55-57 

 Nucleolitcs carinatns Goldfuss, 1826. Petrefacta Germaniae, p. \^2, pi. 43, fig. ir. 



Material. — Over 60 specimens studied in the U. S. National Mu- 

 seum. 



Shape. — Small, elongate, inflated, with posterior margin pointed 

 at periproct, greatest height at apical system or slightly posterior to 

 it, greatest width posterior to center ; adoral surface flattened or 

 slightly convex. 



Apical system. — Anterior, tetrabasal (text fig. 56), four genital 

 pores, pore of genital 3 at greater distance from other pores ; posterior 

 genital plates not in contact, separated by genital 2. 



