384 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



?ee two lateral primitive areas. The lateral avicularia are rarely wanting (fig. 2) : 

 we have observed (fig. 4) an inexplicable case of an avicularian monstrosity. The 

 zooecia apparently never have spines; however, our figure 3 presents some traces 

 of them. 



Affinities. This species differs from Hippomenella angustaedes and from Hip- 

 pomenella transversata in its aperture exteriorly semilunar (and not elliptical) 

 with mucronoid convexity. 



It differs from Hipp <omen ella rotula, from Hippomenella capitimortis. and 

 from Hippomenella costulata in the extremely irregular punctations of its ovicell. 



It differs from all other Hippomenellae in its bilamcllar zoarium. 



Occurrence. Middle Jacksonian : Rich Hill, 5J miles south of Knoxville, 

 Georgia (very common) ; 3J miles south of Perry, Georgia (common) ; 18 miles west 

 of Wrightsville, Georgia (rare) ; 17 miles northeast of Hawkinsville, Georgia (com- 

 mon) ; 3^ miles north of Grovania, Georgia (common) ; Twiggs County, Georgia 

 (several localities) ; 12 miles southeast of Marshallville, Georgia (common) ; near 

 Lenuds Ferry, South Carolina (rare) ; Baldock, Barnwell County. South Carolina 

 (rare) ; Eutaw Springs, South Carolina (common). 



Jacksonian (Zouglodon bed) : Suck Creek, Clarke County, Mississippi (rare) ; 

 Shubuta, Mississippi (very rare). 



Cotypes. Cat. Nos. 64080-64082, U.S.N.M. 



HIPPOMENELLA CAPITIMORTIS, new species. 



Plate 85, figs. 17, 18. 



Description. The zoarium is free, lamellar, formed of two lamellae, back 

 to back, and inseparable. The zooecia are large, elongated, elliptical, or oval ; the 

 frontal is convex, smooth, garnished laterally with a double row of numerous 

 areolae. The orbicular aperture (in the interior) is exteriorly formed of a semi- 

 lunar anter and of a very convex and mucronoid poster. The ovicell is hyper- 

 stomial, embedded in the distal zooecia ; the two lateral areas are perforated by a 

 very large pore in part occupied by a denticle shaped like the head of a lance. 

 The avicularia are absent or very small. 



Measurements. Aperture (7uz=0.20 mm. . /Zs=0. 70-0.90 mm. 



(exterior) Ua=0.15-0.18 mm. ia l?3=0.45-0.55 mm. 



Variations. The rows of areolae are often three in number; on certain parts 

 of the zooecia they have thus the aspect of tremopores. The small avicularia 

 develop in the place of an areola ; they are placed at a distance from the aperture ; 

 they have a pivot and there is only one to each zooecium. The ovicell is very 

 characteristic; it gives the zooecium the vague aspect of a death's head. We are 

 absolutely ignorant of the physiologic use of the large perforations and of the little 

 tongue in the form of a head of a lance which they contain. 



Affinities. This species much resembles Hippomenella semilevis Eeuss, 1869. of 

 the Priabonian. It differs from it in the presence of the little tongue in the pores 



