KOFOID AND MICHENER: DINOFLAGELLATES. 293 



DlNOPHYSIS RUGOSA, Sp. nOV. 



A medium sized species of unique form and structure approaching Histioneis 

 in form of anterior collar. Body rotund, pear-shaped, its greatest diameter 

 twice that at base of posterior collar, and located about 0.33 of length (ex- 

 cluding ventral fin only) from posterior end. Anterior collar sessile, but 

 high, funnel-shaped, and flaring more dorsally than elsewhere, with 10-12 

 ribs on a side and some basal reticulations, its height 0.25 and opening 0.55 

 of the greatest dorso-ventral diameter of midbody, oblique, sloping to the 

 right and ventrally. Posterior collar low, erect, slightly flaring, heavily and 

 finely reticulated to the very margin, its height about 0.13 and its opening 0.7 

 of the greatest dorso-ventral diameter. Both right and left ventral fins 

 heavily reticulated the right low, its height 0.08, and its length 0.75 of greatest 

 dorso-ventral diameter. The left fin continued posteriorly beyond the ant- 

 apex 0.46 of the greatest dorso-ventral diameter, to an acute point. Fission 

 ribs at level of posterior third of body, slanting at 20° from horizontal. Total 

 length of left fin 1.5 and greatest width about 0.25 of the greatest dorso-ventral 

 diameter. Surface finely, deeply, and regularly pitted. 



Length, of body 43 m, total, 74 n) greatest dorso-ventral diameter, of body, 

 42 n, total, 50 M - 



Sta. 4705. 



Amphisolenia astragalus, sp. nov. 



Allied to A. bidentata Br. Schroder but with less ventral curvature of the 

 antapical region and a distinctly foot-like antapex. Length forty times 

 greatest dorso-ventral diameter. Well differentiated midbody extending 

 posteriorly one half total length from head. Greatest dorso-ventral diameter 

 0.4 of total length from head, about three times same diameter distally. 

 Flagellar pore 0.12 of total length from head. Head subglobular, its dorso- 

 ventral diameter less than that of midbody, and three times that of neck. 

 Furrow ribbed, lists very wide, ribbed. Antapex foot-like with distinct heel 

 and ventral extension, varying in position between horizontal and posterior 

 deflection of 45°, armed distally with two short, stout, terminal spines. The 

 antapical region is curved a little to the left. 



Length 650 n; transdiameter, 16 n. 



Sta. 4713. 



Amphisolenia quadricauda, sp. nov. 



Belongs to the A. thrinax group but has three ventral branches instead of 

 two {A. thrinax Schutt) or four (A. quinquecauda Kofoid). Body expanded 

 into fusiform midbody about 0.2 of the total length in length, its greatest 

 dorso-ventral diameter located at 0.25 of total length from the head, and five 



