Dr. H. Woodward—On a Fossil Schizopod Crustacean, 401 
many examples of Pygocephalus from the Clay-ironstone nodules of 
Coal-measure age at Coseley, near Dudley, now in the Geological 
Department of the British Museum (Natural History Branch), 
Cromwell Road, S.W. These specimens are preserved in great 
perfection, and I had fully intended to figure them some years ago, 
but the pressure of other work caused them to be set aside for 
a time. Last year I received an example of Pygocephalus from 
Mr. Walter Baldwin, F.G.S., obtained from the Clay-ironstone of 
the Middle Coal-measures at Sparth, Rochdale (for description see 
Fig. 1, p. 405). I have also received through Mr. H. A. Allen, 
F.G.8., of the Geological Survey Museum, Jermyn Street, by the 
kindness of their owner, Mr. Herbert Hughes, Assoc. R.S.M., F.G.S., 
of Horseley House, Wolverhampton Street, Dudley, four most 
interesting specimens of Pygocephalus collected by him, two of 
which prove to be females, a point of extreme interest not heretofore 
observed. 
In his original paper (Quart. Journ. Geol. Soc., 1857, pp. 8638-36, 
pl. xii) Professor Huxley gave a very complete description of the 
underside in the male of Pygocephalus Coopert, and, in the figures 
accompanying his paper, he shows the hexagonal plates forming the 
sternites of the thoracic segments; to the lateral marginal plates are 
attached the coxopodites of the thoracic limbs (pereiopods). He had 
also determined the presence of a distinct endopodite and exopodite 
to each thoracic limb. He writes as follows (p. 365) :—‘‘ Attached 
to the outer boundaries of the lateral (ventral) plates, seven 
appendages are observable on one side and six on the other. In 
the more perfectly preserved appendages (fig. le) there may be 
distinguished a short, proximal, convex, subcylindrical joint, followed 
by at least three other slender and delicate articulations; of these 
the proximal one is the longest, the terminal next in length, and 
the middle one shortest. The terminal joint exhibits indications of 
further subdivision. 
“The fifth limb on the right side presents a very important 
character, inasmuch as there les parallel with and behind it a 
delicate, curved, many-jointed filament (fig. 1c), which externally 
abuts against the terminal joint of the appendage, and internally 
les parallel with the longer cylindrical joint, and in close contiguity 
with the basal division of the appendage. I believe, in fact, that 
this filament is nothing less than the outer division of the appendage, 
or its exopodite ; and I am inclined to think that traces of a 
corresponding filament are visible in some of the other appendages.” 
On p. 367 he concludes further that “‘the small internal pair of 
appendages are the antennules, the large external ones antenne; 
the seven segments are the sterna of seven thoracic somites, 
increasing in width from before backwards; the narrow longi- 
tudinal plates (lying outside the margin of the thoracic sternites) 
are the edges of a short carapace; and the semicircular disk is the 
1 Since penning the above I have discovered two imperfectly preserved females of 
Pygocephali amongst Mr. Henry Johnson’s specimens (registered number I, 1536) from 
Coseley, near Dudley, to be presently referred to again. 
DECADE V.—VOL. IV.—NO. IX. 26 
