288 bulletin: museum of comparative zoology. 



OXYTOXUM RECURVUM, sp. I10V. 



A medium sized species resembling 0. cristatum Kofoid (1907), pi. 10, fig. 64, 

 but with long, spinulate apex curved to the left and dorsally, and a fuller 

 hypotheca. Body irregularly and asymmetrically biconical, girdle 0.46 of 

 total length from apex. Length 0.48 transdiameter. Epitheca a low cone 

 whose completed altitude would be 0.5 transdiameter, with a somewhat 

 abruptly continued apex in the form of an elongated, tapering, curved, or 

 even recurved horn, deflected to the left and dorsally, its length attaining in 

 some cases 0.5 transdiameter. Hypotheca 1 transdiameter in altitude, its 

 dorsal outline straight, the laterals and ventral convex, contracted dorsally 

 to a stout, acute ant apical horn, 1.4 girdle widths in length. Girdle descend- 

 ing, displaced 1 girdle width. Ventral area very short. Hypotheca ribbed. 



Length, 75 /j.; transdiameter, 40 n. 



Sta. 4724. 



OXYTOXUM ROBUSTUM, Sp. 110 V. 



A stout species of medium size allied to O. compressum Kofoid but differing 

 from it in absence of lateral compression, and in higher epitheca. Body 

 nearly biconical in ventral view. Length 1.6 transdiameter. Girdle section 

 circular. Epitheca 0.5 to 0.75 altitude of hypotheca, 0.67 transdiameter in 

 altitude, with subcorneal outline in lateral view, and with concave sides, 

 rounded apex and flaring girdle in ventral view. Hypotheca conical with 

 acute apex curved ventrally, its total ventral altitude 1 transdiameter. Ant- 

 apical spine scarcely differentiated. Girdle descending, displaced 1 girdle 

 width, its proximal end excavating a rounded pit in margin of epitheca, deeply 

 impressed, without lists. Ventral area 1 girdle width across and 3.5 in total 

 length. Sutures marked by single ribs on hypotheca and by smooth inter- 

 calary bands with bounding ribs on main sutures of epitheca. Girdle ribbed, 

 surface of plates finely and regularly reticulate. 



Length, 97 /*; transdiameter, 60 ac. 



Sta. 4679. 



Phalacroma circumcincta, sp. now 



Resembling P. vastum, but differing in greater elongation of body, position 

 of girdle, and surface markings. Length 1.36 dorso-ventral diameters. Body 

 asymmetrically elliptical in lateral outline which the girdle scarcely modifies. 

 Girdle 0.42 to 0.44 of total length from apex. Girdle lists horizontal, low, 

 hyaline, without ribs, less than girdle width in height. Low sagittal fin on 

 both epitheca and hypotheca, incomplete dorsally. Ventral fins low, 1 to 1.5 

 girdle widths in height, sometimes reticulated. Surface minutely and closely 

 pitted by somewhat irregular pits, about 35 across the side at girdle, larger 

 next to girdle. 



