188 bulletin: museum of comparative zoology. 



Length, 80 /x; dorso-ventral diameter, 23 \i. 

 Station, 4732. 



Oxytoxum compressum, sp. nov. 



Plate 10, Fig. 63. 



A medium-sized species resembling 0. cristaturn, but lacking the galeate apex, 

 and having the antapical horn strongly deflected to the ventral side. 



Body elongated, laterally compressed. Total length 2 times the transdiam- 

 eter and 1.6 times the dorso-ventral. Epitheca 0.25 the total length, low cam- 

 panulate or dome-shaped, flaring at the girdle, apex blunt, broadly rounded. 

 Altitude of epitheca 0.5 of the transdiameter and 0.35 of the dorso-ventral 

 diameter. 



Hypotheca elongated, its length 1-1.4 times the dorso-ventral and 1.5 the 

 transdiameter. Dorsal and ventral margins somewhat convex, gradually 

 rounded posteriorly to the hook-like ventrally recurved antapical spine. Lat- 

 eral margin but slightly convex, abruptly contracted to the antapical. 



Girdle narrow, horizontal, ribbed, furrow deeply impressed with salient 

 ridges, forming a descending right spiral displaced its own width, without 

 overhang. Longitudinal furrow short, its length 0.3-0.4 of the total length, 

 equally extended on both sides of girdle, both ends expanded. 



Pre- and postcingular plates normal, apicals and antapicals not resolved into 

 separate parts. Postcingulars with marginal and median striae, which are 

 faintly outlined on epitheca also. Wall porulate. 



Length, 100 /x; dorso-ventral diameter, 62 aa. 



Stations, 4699, 4724. 



Oxytoxum cristaturn, sp. nov. 



Plate 10, Fig. 64. 



A medium-sized species with elongated laterally compressed body, galeate 

 epitheca, and long antapical spine. 



Total length 2.5 times the transverse and 1.85 times the dorso-ventral diam- 

 eter. Epitheca 0.4 of the total length, helmet-shaped, with flaring base ab- 

 ruptly compressed laterally to a thin dorsal ly recurved apex. Apex a sharp 

 horizontal, or even posteriorly deflected spine. Transverse diameter of the base 

 0.75 of the dorso-ventral and 0.9 of the altitude. 



Hypotheca tapering obliquely to the ventral side, laterally compressed, lateral 

 margins slightly convex, dorsal broadly rounded, ventral concave, abruptly 

 contracted to a long, tapering, ventrally deflected, antapical spine, 0.4-0.6 of 

 the transdiameter in length. 



Girdle narrow, with salient margins, furrow impressed, forming a descending 

 right spiral displaced its own width, no overhang, and with numerous stout 

 ribs. Longitudinal furrow short, length 0.3 of the total length, nearly 0.6 of 

 its course on the epitheca, elongated elliptical in form. 



Neither apical nor antapical region resolvable into separate plates. Pre- and 



