216 DR. J. MURIE ON THE ANATOMY [Feb. 14, 
figure given by Eschricht and Reinhardt* of the skull of Baleno- 
ptera musculus, J. Mill. (= Physalus antiquorum, Gray) may be said 
to convey a fair idea and representation of it. 
The two outer borders of the superior maxillaries at the base of 
the beak run nearly parallel for about their posterior half, whence 
they incline gently towards each other; but in the anterior fourth 
they approach more quickly to the narrowed tip of the beak. The 
nasal processes of the same bones are flattish, and at the nasal fossa 
have a sharp internal edge; but on reaching the posterior end of the 
premaxillaries they slope outwards and downwards, forming the 
posterior superficial curve of the rostrum; at the tip of the beak, 
however, they again become nearly horizontal. 
The premaxillaries, on the other hand, at their posterior ends 
are almost vertical, and look towards each other in the nasal fossa, 
while they become horizontal in the middle of the beak, and shelve 
outwards at the tip. The frontal bone im the median line of the 
skull is represented merely by its nasal tuberosity, which is wedged 
in behind the nasal bones; but the orbital plates occupy a great 
flattish expanse on either side, and look directly upwards. The 
cavity of the orbit is ovoid, with a height of 73 and a breadth of 
10 inches. 
The malar bones are present, flattened, and of a comparatively 
small size ; their maxillary process is broader than their zygomatic. 
The prominence of the cranium formed by the supra-occipital pre- 
sents a very slight concavity, with just an appreciable median ridge. 
Posteriorly the occipital region shelves sharply downwards and back- 
wards, and has aconsiderable concavity. The occipital foramen and 
condyles are directed straight backwards. This posterior occipital 
inclination does not seem so sharply defined in the young skull of a 
Physalus antiquorum in the Museum of the College of Surgeons 
(no. 2446 A, Osteological Series). The vomer reaches within a foot 
of the anterior tip of the premaxillaries ; along with the superior 
maxillaries, it forms a marked palatine ridge in the roof of the mouth. 
The inferior maxillary bones have acuminated coronoid processes, 
which are bent outwards at their extremities. The condyles are set 
backwards and a little outwards, externally overlapping the groove 
of the neck. The rami are strong and with a moderate lateral curve. 
The following are a series of measurements of the skull, taken in 
inches, and in the manner followed by Mr. Flower (P. Z. 8. 1864, 
p- 411); so that the dimensions of the cranium of this specimen may 
readily be compared with the examples of Physalus antiquorum given 
in the above paper. 
inches. 
Length of skull sngstemielat ites ier tei + fuse nian aio: alee, e, «ol 168 
Breadth; of, come yew: cyere se eee sil jot is Jie 9s; viele 12 
Breadth of squamosals (greatest breadth of skull) ........ 82 
Orbital process of frontal, length .. 0.0... 20.0 cecssscces 30 
Orbital process of frontal, breadth at base................ PH 
Nisa, Repti ates nicsyexel a - (tie Sin amet Sypris Beem eens gga hoe 84 
* Om Nordhyalen, 1861, tab. 3. fig. 5. 
