KOFOID AND MICHENER: DINOFLAGELLATES. 301 



ventral diameter. Anterior and posterior collars subequal in dorso-ventral 

 diameter. Anterior with simple, straight major ribs and minute peripheral 

 riblets, or with sparse, irregularly curved and anastomosing ribs and reticula- 

 tions. Posterior with stouter simple ribs. Form and proportions about as 

 in 0. serratus Kofoid. Sagittal fin complete, with straight dorsal margin 

 and circular outline to ventral lip of posterior collar, with seven or eight 

 major simple, or basally bifurcated ribs breaking distally into feebly developed 

 marginal reticulations. Surface coarsely reticulate, each polygon or pit with 

 pore, 15 behind girdle. 



Length, of body, 65 n, total, 115 n] dorso-ventral diameter, of body, 70 /x, 

 total, 115 (*. 



Possibly a phase in thecal reconstruction. 

 Sta. 4617. 



Berghiella, gen. nov. 



With the form of a spheroidal Gonyaulax with very abruptly differentiated 

 low cylindrical apical horn with truncate apex. Girdle with hyaline lists, 

 descending, displaced less than a girdle width, not impressed. Ventral area 

 not delimited posteriorly. Absolutely no trace of subdivision of theca into 

 plates or regions. Type species B. perplexa. 



Berghiella perplexa, sp. nov. 



Body, excluding apical horn, a short ellipsoid with vertical axis (excluding 

 horn) 1.12 transdiameters, with horn 1.25. Girdle section circular. Apical 

 horn low, stout, apex squarely truncated, its height 0.16, its diameter at base 

 0.24, and at apex 0.19 transdiameters. Girdle equatorial, posterior list of 

 proximal end half way between base of apical horn and ant apex, the epitheca 

 thus slightly exceeds hypotheca; descending, displaced distally 0.33 girdle 

 width, not impressed, its sides formed by thin hyaline structureless lists, 0.6 

 girdle width in height. A narrow crease runs forward from the junction of 

 the girdle-ends nearly to base of apical horn. Ventral area suggested by short 

 posterior extensions of the posterior list at the two ends of the girdle. A small 

 pore (flagellar pore?) lies in this territory. Surface without trace of sutures, 

 or marked reticulations, minutely and evenly flecked by the faintest suggestion 

 of areoles. A single line of pores anterior to the girdle. Contents highly 

 vacuolated, completely filling the theca. Nucleus elongated, reniform. 



Length, 65 n; transdiameter, 50 n. 



Stage of growth, relationships, and even orientation problematical. 

 Sta. 4670. 



Amphitholus quincuncialis (Kofoid). 



Described by oversight as Amphiloikus quincuncialis in my earlier 

 (1907) paper. 



