196 bulletin: museum of compaeative zoology. 



The hypotheca is deeply and broadly bifurcated by a wide arc which reaches 

 the posterior end of the longitudinal furrow. The depth of the bifurcation 

 is but little less than the dorso- ventral diameter of the body in the girdle. 

 As a result of the bifurcation there are two slender tapering acute horns, a 

 shorter ventral and longer dorsal. Their length is about 0.75 of the distance 

 between their tips. 



The girdle is wide, with flaring sub-horizontal lists. The longitudinal furrow 

 is turned abruptly to the right and runs on the right face of the organism to 

 the dorsal side of base of the ventral horn. The suture between the valves 

 follows this course and then turns abruptly toward the ventral margin of the 

 horn. 



There is a low ridge on the right side of the furrow which continues as a 

 short spine beyond the posterior margin of the body. 



Length, 60 fi ; dorso- ventral diameter, 38 fi. 



Station, 4711. 



Dinophysis triacantha, sp. nov. 



Plate 13, Fig. 74. 



Related to D. schiitti Murr. et Whitt. and D. uracantha Stein. Resembles 

 D. uracantha in having marginal ribs to the postero-dorsal spine. Diflfers from 

 both of these species in the presence of a third spine in the ventral fin, located 

 at its dorso-posterior margin and formed as in the case of the postero-dorsal 

 spine by marginal thickenings. 



Body broadly ovate in lateral view, anterior collar unevenly ribbed, ventral 

 fin feebly reticulated. Thecal wall with fine irregular reticulations, a few of 

 which contain pores. The three spines subequal, in length about 0.5 of the 

 dorso-ventral diameter of the body. 



Length of body without spines or collar, 50 /x; greatest dorso-ventral 

 diameter, 50 /x ; spines, 20-25 fx. 



Station, 4722. 



Amphisolenia asymmetrica, sp. nov. 



Plate 13, Fig. 76. 



An elongated species resembling A. dolichocephalica. Total length nearly 

 twenty-five times that of the neck and nearly fifty times the dorso-ventral 

 diameter of the midbody. Head long, narrow, oblique, its long axis slightly 

 exceeding the neck in length, with low .spreading sparingly ribbed lists. Antap- 

 ical stem curved ventrally and distally deflected abruptly to the right, bearing 

 a short spine in the left face at the point of deflection and three equidistant 

 terminal spinules on the slightly swollen end. Walls thickened distally along 

 sutures which do not follow the median plane of symmetry through the appa- 

 rently twisted antapex but divide it into two asymmetrical valves, the right with 

 two terminal spinules and the left with one terminal and the lateral. 



Nucleus elongated, chromatophores few, large, ellipsoidal. 



