1912] Kofoid-Uichencr: Dinosphaera palustris 23 



The postcingiilar series in Dinospliacra begins with the large 

 plate, the homologue of postcingular 2' " of Gonyaulax, and there 

 are but five postcingulars in all, exactly as stated by Lemmer- 

 mann. On the other hand we find absolutely no trace of any pos- 

 terior accessory plate. Lemmermann distinctly states that such a 

 plate is present, but his figures 1, 4, and 5 do not delineate it. It 

 is possible that one of the subdivisions (called by us the posterior 

 plate) of the ventral area (Langsfurche) on the lower margin 

 of his figure 5 was accidentally interpreted by him as an accessory 

 plate. We find no homologue to the posterior accessory of 

 Gonyaulax in Dinosphaera and no grounds for interpreting the 

 posterior plate of the ventral area as the posterior accessory. 

 Lemmermann 's ventral view (fig. 1) does not clearly integrate 

 this region as a distinct plate. 



Since Gonyaulax palustris thus lacks two of the three essen- 

 tial plate characteristics of the genus Gonyaulax in the most 

 conservative part of the skeleton it seems necessary to provide 

 otherwise for its classification. "We accordingly propose the new 

 genus Dinosphaera for its reception and append herewith a brief 

 description, including therein a few additional facts concerning 

 the structure of the girdle and ventral area and our analysis of 

 the skeleton. 



Dinosphaera gen. nov. 



Skeleton consisting of an apical series of plates, six pre- 

 cingulars, six girdle plates, five postcingulars and one antapical. 

 Type species Z>. paZitsim (Lemm.) 



Dinosphaera palustris (Lemm.) Kofoid and Michener 



Diagnosis. — Body subspheroidal, girdle almost equatorial, 

 slightly displaced distally. Ventral area shallow, widened an- 

 teriorly to 0.3 trausdiameter. Plate formula 3', 1", 6", 6, 5' ", 

 C, 1" ". No apical pore. Surface smooth, sparingly porulate. 



Description. — Body subspheroidal, length not exceeding 1.05 

 transdiameters, dorso-ventral and transverse diameters equal. 



