1920] 



Eeiv: Cretaceous and Cenozoic Echinoidea 



137 



margin. The main furrows are broad, shallow, and straight, deep- 

 ening as the ambulaeral notches are api^roaehed. Mouth small and 

 not sunken. Anus situated on the inferior surface slightly anterior 

 to the interambulacral lunule. 



Related forms. — This species closely resembles the Recent Encope 

 calif ornica Verrill. Tlie latter differs in its thicker margin and usually 

 closed ambulaeral notches. 



Geologic horizon. — Lower division of the Carrizo Creek beds, 

 Pliocene. 



Locality. — Coyote Mountain, Imperial County, California. Co- 

 types from Univ. Calif, loc. 2064. 



Genus MELLITA Agassiz 



MELLITA LONGIFISSA Miehelin 

 Plate 38, figures la, 15, Ic, Id, le 



Mellita longifissa Miehelin, Eev. Mag. Zool., no. 8, 1858. 

 Mellita longifissa. A. Agassiz, Eevision of the Echini, Mus. Comp. Zool., 

 III. Cat., no. 7, pt. 1, 1872-74, p. 535, pi. 11, figs. 24-27. 



Figured specimen. — No. 11025 Univ. Calif. Coll. Invert. Pal. 



Test of medium size. Measurements of specimen no. 11025: antero- 

 posterior diameter 70 mm., transverse diameter 75.5 mm., greatest 

 height 10 mm. Outline broadly subovate ; rounded posteriorly, with 

 a faint, broad marginal notch in the odd posterior interambulacral 

 area ; greatest width posterior to the center of the test. Margin very 

 thin, slightly thicker in front. Apex anteriorly eccentric ; upper 

 surface sloping with an even profile to the rear, and to the anterior 

 margin with a more or less rounded one. Lunules narrow and slit- 

 like ; odd posterior one the longest, the two anterior the shortest. 

 Apical system anteriorly eccentric to a slight degree, and behind the 

 summit. Madreporic area large ; four genital i^ores and five small 

 perforated radial plates. Petals unequal in length ; posterior pair the 

 longest and slightly curved backward ; anterior lateral pair consider- 

 ably shorter, with the odd one slightly shorter than the posterior 

 lateral pair. Poriferous areas wide, each zone being broader than 

 the interporiferous area, with the exception of the odd anterior petal, 

 in which the interporiferous area is wider than each poriferous zone. 

 Inner rows of pores extend in approximately parallel lines to the 



