ALBTJLTD^. 
61 
1891-93. Pisodus oiveni, A. S, Woodward, Geol. Mag. [3] vol. viii. 
p. 108, pi. iii. figs. 3-5, and Ann. Mag. Nat. Hist. [6] vol. xi. 
p. 357, pi. xvii. 
Type. Parasphenoid dentition ; Eoyal College of Surgeons, 
London. 
The type species of the so-called genus Pisodus., of large size, 
the head sometimes attaining a length of 0-3. Too imperfectly 
known to be precisely defined, but differing from the sole existing 
species in the proportions of the cranium ; the distance from the 
end of the snout to the anterior notch of the frontals being about 
equal to that from this notch to the occiput, whereas the proportion 
of the same measurements in the recent A. vulpes Ms 2: 3. Rostrum 
thus comparatively large. 
Form. Log. Lower Eocene (London Clay) : Sheppey. Similar 
tritoral teeth in Middle Eocene (Bruxellian) : Brussels. 
P. 9158. Head with opercular apparatus, remains of the pectoral 
arch, and fragmentary scales ; London Clay, Sheppey. 
The skull measures about 0‘3 from the occiput to the end 
of the snout, and the cheek has a very similar aspect to 
that of the recent species. The specimen is crushed 
obliquely, so that the roof of the cranium is shown entirely 
on the left side (PI. IV. fig. 1 a), while the space below 
and behind the mandible, with some of the branchiostegal 
rays, appears on the right side (fig. 1). The whole of 
the fossil is permeated with pyrites, which may decay and 
eventually cause its destruction. Of the cranium itself 
only the roof is exposed, but this is complete and merely 
a little fractured and in places obscured by pyrites. 
Behind the occiput the epiotic {ep.o.) is distinct on the 
left side ; the limits of the squamosals {sq.), parietals {pa.), 
and frontals {fr.) are sufficiently clear. The postfrontal 
(pt.f.) is also exposed a little, and the prefrontal {pr.f.) 
still more on the cranial roof; and the form of the median 
depression in this roof is characteristically exhibited. 
The rostrum is comparatively long and slender, too im¬ 
perfect for description ; but the notch in the anterior 
border of the frontal is distinct on each side, this beino' 
situated about midway between the occiput and the end 
of the snout. Remains of the mandibular suspensorium 
and jaws are exposed on each side of the fossil; and the 
remarkably forward articulation of the mandible is well 
^ See figure by Shufeldt, Eep. U. S. Fish Comm. 1883 (1885), pi. xiii. fig. 30. 
