360 University of California Publications. | ZooLocy 
The postmargin is not set off from the inner margins of the an- 
tapicals with which it forms a fairly regular are. The distance 
between the tips of the antapicals is 0.4 transdiameters. 
The girdle is postmedian, reniform in cross section, though 
somewhat thicker on the left side, and nearly perpendicular to 
the main axis. The transverse furrow is deeply indented with 
heavy overhanging anterior list and less strongly developed pos- 
terior one which vanishes distally on the ventral suture of the 
right antapical horn. The furrow is wide, postero-dexiotropic 
with a displacement equalling its width. The longitudinal fur- 
row is about 0.6 distance to postmargin in length and is wide 
and shallow. 
The plates of the theea are typical, the left interecalary being 
almost wholly confined to the dorsal face and of small size. Both 
pre- and postmedians are irregular in size and arrangement. 
There is an unusually large ventral area in the midventral suture 
of the epitheca which is deflected to the left and contains the 
reniform ventral pit. The suture lines are well developed and 
are laticed in places. Hyaline lists are found on the lateral and 
postmargins of the hypotheca. The thecal wall including the 
eirdle is coarsely and irregularly reticulate with well developed 
polygons of 3-5 sides, each with a single central pore. Near 
the lateral margins of the epitheca these polygons are somewhat 
recular and often quadrangular. There are 108 in the dorsal 
apical plate. 
The plasma and indeed the whole organism is beautifully hya- 
line. There are a few subspherical greenish chromatophores and 
an ellipsoidal nucleus near the flagellar foramen. 
Dimensions :—length, 140-1554; transdiameter, 100-105, ; 
dorso-ventral diameter, 602; width of transverse furrow, 10-12,; 
polygons 4-8p, rarely 12p. 
Taken in vertical hauls from 95 fathoms off San Diego in 
June. 
I regard H. scrippsi as the type species of the genus. 
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