182 bulletin: museum of comparative zoology. 



with oblique apical pore deflected to the right. The ventral area is poorly 

 defined and the pit is located far anteriorly. 



The hypotheca is low dome-shaped with two short, acute, unequal, widely 

 separated divergent antapicals. The left is 2-3 times the length of the right, and 

 the distance between their tips is 0.45 of a transdiameter. The postindentation 

 is very shallow and the postmargin a broad, irregular curve. 



The girdle is slightly oblique, is displaced less than its own width, lacks the 

 posterior list entirely. The furrow is not impressed, and is marked by sparsely 

 distributed reticulations. 



The plates are normal. The left intercalary is of medium size. The wall is 

 porulate in the central areas of the plates, which are imperfectly reticulate or 

 bounded by ridges. The suture lines are bounded by broad, structureless 

 bands. 



Length, 117 /x; transdiameter, 82 fi. 



Stations, 4691, 4692, 4699. 



Heterodinium hindmarchi, forma maculata, f. nov. 



Plate 7, Fig. 48. 



Distinguished from the typical H. hindinarchi by the character of the re- 

 ticulations. The form, proportions, and dimensions resemble those of the 

 species named, but the reticulations are entirely diff'erent. In the type they 

 are coarse and subregular. In f. maculata they are exceedingly diverse in 

 size. Distally on the apical and antapicals, the minute reticulations pre- 

 dominate. In the pre- and postcingular plates they are predominately mar- 

 ginal in the plates or intercalated in more or less complete horizontal series. 

 They are also found in isolated and irregular groupings. Possibly such 

 diff'erences here constitute a specific distinction. 



Length, 140 ;i; transdiameter, 80 /x. 



Station, 4691. 



Heterodinium laticinctum, sp. nov. 



Plate 7, Fig. 46. 



A moderately large species with very oblique, very wide girdle, broadly 

 rounded apex, angular hypotheca, and incurved unequal antapicals. 



The body is robust, ovate in ventral view, its length 1.4 times the trans-, 

 diameter and 1.8 times the dorso-ventral. The apex is semicircular in outline. 



The epitheca is low scoop-shaped with slight excavation, foreshortened dor- 

 sally so that the dorsal precingulars are scarcely as wide as the girdle. The 

 apical pore is displaced to the right. The ventral area is displaced to the left, 

 is subcircular with eccentric pit. 



The hypotheca is a little longer than the epitheca. Its sides are slightly 

 convex, and the antapicals are incurved and very acute. The left is twice the 

 length of the right. They arise toward the ventral face and make a sharp offset 

 dorsally to meet the postcingular suture. 



