CLABK.] CATOPYGUS PUSILLUS. 65 



ApicaUliskexcentric, nearer the anterior border. Mouth opening small, 

 excentric, nearer the anterior margin. Anal opening oval, situated in a 

 narrow sulcus, that terniinatos above in a projecting arch. 



Dimensions. — Length, J inch; width, -^ mvAi; lieight, -i"^ inch. 



Description. — The test of this very beauti ful little form is ovate, with 

 rounded, inflated sides and elevated upper surface. The base is nearly 

 flat, slightly concave in the vicinity of the mouth edges, and lobed pos- 

 teriorly. 



The auibulacral areas are narrowly lanceolate, subi)etaloidaI on the 

 upper surface, the two posterior areas being much longer than the 

 others. The plates in the petaloidal portions are narrow, but beyond 

 increase in breadth (PL xxvii, Fig. 2e). 



The large interambulacral plates are covered with minute tubercles, 

 between which are numerous microscopic granules. 



The apical disk is suiall, excentric, and situated far anterior to the 

 apex (PI. XVII, Figs. 2a, 2c). 



The mouth opening is small and situated nearer the anterior margin. 



The anal.opening is oval and jilaced at the upper part of a nearly verti- 

 cal anal sulcus. The upper margin of this sulcus forms a beak-shaped 

 prominence that overhangs the opening (PI. xxvii. Fig. 2d). 



Belated forms. — It is separated from C. pusillus Clark, the other 

 American species, by its narrower outline, more inflated sides, and the 

 anterior position of its apical disk. In form it is somewhat like G. 

 columbarius, which is widely distributed in the Cenomanian of Europe, 

 but the position of the apical disk at once distinguishes it. 



Locality and geological horizon. — This species is from the yellow 

 limestone of the middle marl bed (upper Cretaceous) of Timber creek, 

 New Jersey. 



Collection. — Philadelphia Academy of Natural Sciences. 



CATOPYGUS PUSILLUS Clurk. 



Plate XXVII, Figs. 'Sa-d, 



Catopygiis pusillus Clark, 1891. Jolina Hopkins University Circulars, No. 87, p. 76. 



Determinative characters. — Test ovate to subquadrate, rounded an- 

 teriorly, subquadrate posteriorly, broader behind than before; upper 

 surface elevated; base coucave. Ambulacra narrowly lanceolate, sub- 

 petaloidal on the ui>per surface. Apical disk small, nearly central. 

 Mouth opening small, anteriorly placed. Anal opening oval, in vertical 

 sulcus beneath overhanging arch. 



Dimensions. — Length, f inch ; width, 1% inch ; height, | inch. 



Description. — All the specimens of this species examined by the writer 

 are casts, that are, however, sufiiciently well preserved to admit of the 

 determination of all the more important characters. The test is ovate 

 to subquadrate, occasioned by the slight angularity of the posterior 

 margin. The anterior jjortiou is regularly rounded. 

 Bull. 97 5 



