UNIVERSITY OF CALIFORNIA PUBLICATIONS 
ZOOLOGY 
Vol. 9, No. 8, pp. 353-357 September 14, 1912 
HAECKEL’S SETHOCEPHALUS EUCECRY- 
PHALUS (RADIOLARIA) A MARINE 
CILIATE 
BY 
CHARLES ATWOOD KOFOID 
(Contribution from the Scripps Institution for Biological Research) 
In his Prodromus (1881) Haeckel proposed the genus Platy- 
cryphalus for a radiolarian with a bicamerate fenestrated shell 
with a transverse stricture separating it into a primary chamber, 
or cephalis, and a secondary basal one, or thorax. The shell was 
without ribs, open, with obtusely rounded, smooth, non-spinous 
cephalis and spreading, open, almost disk-like thorax. No species 
was mentioned in this article and naturally no type species is 
available. However, in his Report on the Radiolaria (1887, p. 
1298) Haeckel quotes ‘‘Platycryphalus sethodiscus, Haeckel, 
1881, Prodromus, p. 480’? as a synonym of his Sethocephalus 
platycryphalus n. sp., though no such species appears on this 
page, or elsewhere, in the article quoted. 
The location in the system assigned to this organism is as 
follows: Class Radiolaria, Order Monopylaria, family Cystida, 
subfamily ‘‘Dyoecyrtida,’’ tribe Sethocorida, genus Platycry- 
phalus. 
In the corresponding location in his Challenger Report he 
(1887) proposes the genus Sethocephalus with the definition 
““Sethocorida (vel Dyeyrtida eradiata aperta) with discoidal, 
flatly expanded thorax. Cephalis large, without horn.’’ He 
describes in this genus two species, Sethocephalus eucecryphalus, 
which he figures (pl. 56, fig. 13), and S. platycryphalus, to 
