1912 | Kofoid: Sethocephalus cucecryphalus 355 
13) rather than his statements of dimensions in text. The com- 
parison is made in the following table: 
TABLE OF MEASUREMENTS (in microns.) 
Sethocephalus eweecryphalus Cyttarocylis cassis 
Haeckel var. 
Haeckel plagiostoma Daday 
Haeckel (1887, pl. 56, 
(1887, p. 1298) fig. 13) IEntz (1887, p. 58h). 
Total length 140 115 135 
Length of bowl 120 105 126 
Length of collar 20 10 9 
Width of bowl 120 110 117 
Width of aperture 90 95 108 
The meshwork as figured by Daday (1887) is more angular, 
and there is less contrast between that of the bowl and that of the 
collar; in faet, the elements of the collar are smaller than those 
of the bowl, rather than larger as in Haeckel’s figure, and the 
apex is slightly pointed. Daday also correctly figures the wall 
as a meshwork whose openings are filled with a ground sub- 
stance, wholly omitted in Haeckel’s figure. These are consider- 
able differences, and, if they stood alone without further evidence, 
might well obscure the close relationships or identity of the two 
organisms. 
The publication of Brandt’s (1906, 1907) exhaustive mono- 
eraph on the Tintinnodea of the ‘‘Plankton Expedition’’ has, 
however, revealed (1) that Cyttarocylis cassis var. plagiostoma 
Daday is in reality specifically distinct from C. cassis, being 
a small species of more rotund form, more sharply set-off collar, 
and different proportions, and (2) that the range of variation 
within the species is very great. Brandt distinguishes three 
varieties, one of which, var. e (as represented in his pl. 36, 
figs. 3 and 6) most closely resembles the organism figured by 
Haeckel. This variety has, moreover, the broadly rounded apex, 
the rounded meshwork, the coarser, less regular mesh in the 
collar which characterize Haeckel’s figure, and its dimensions 
(length 115-140 ,) fall within those given by Haeckel. Brandt 
also reports this variety from South Pacific waters (off Sidney ) 
whence came Haeckel’s material (Challenger Station 285, 32° 36’ 
Sa Late 43" Wie): 
