524

16

reappears as a separate styliform rib. The first four cervical vertebrae have each a
single posterior hypapophysis ; the sixth to the tenth inclusive have a pair of parapo-
physes simulating anterior hypapophyses.

The parapophyses begin to project downward in the sixth cervical, increase in size
and converge to the ninth, and at the tenth have a common median base, like a
bifurcate anterior hypapophysis ; in the eleventh cervical they disappear, and are
replaced by a true hypapophysis from the mid line of the under surface of the centrum:
it is a compressed subquadrate plate, decreasing in length in the three succeeding
cervicals, in the last of which the parapophyses reappear as short horizonatally extended
plates, the origins of which, approximating in the second dorsal, combine in the third to
form the lamelliform stem of a pair of diverging plates, which decrease in size in the
fourth with antero-posterior increase of the base of the stem, and in the fifth dorsal are
reduced to an expansion of the end of the stem, which now has reassumed the character
and position of a compressed lamelliform hypapophysis, which gradually diminishes to
the last dorsal 1. In the sacrum it is represented by a hypapophysial ridge, which
subsides in the fourth of the coalesced series of vertebrae.

In Alca impennis the lamelliform hypapophysis first appears on the tenth vertebra, is
reduced to a tubercle on the twelfth, and disappears on the thirteenth and fourteenth.
The fore part of the sacrum is carinate below in the penguin, but not in the Garfowl.
The number of free caudal vertebrae is eight in the Penguin, eleven in the Garfowl.

The cranial part of the skull is proportionally larger and longer in the Penguin ; it is
smooth and more convex above ; neither the temporal nor superorbital glandular depres-
sions meet at the mid line, and the temporal depression is narrower above, and is not
divided into an anterior and posterior facet as in the Garfowl. In Eudyptes chrysolo-
phus the glandular depressions are large, deep , and meet for a short extent anteriorly :
the temporal fossae are more than an inch apart on the calvarium. The cerebellar
prominence projects much further at the back of the skull in the Penguin than in the
Garfowl. The paroccipital process is stronger than the mastoid, whilst in the Gar-
fowl they are equally developed. The condyles of the tympanic are bent more back,
the orbital process of this bone is relatively shorter, and the distal articular end is
narrower, in the Penguin. The pterygoids are more expanded anteriorly ; the palatines
are broader, and are convex below, in the Penguin, instead of being concave.

The nasal bone retains its distinctiveness from the premaxillary and maxillary in the
Penguin and has coalesced only with the frontal and prefrontal posteriorly ; its maxil-
lary prong is inclined more forward, at an acuter angle with the premaxillary prong,
than in the Garfowl, and it ends in a free point. The lacrymal is broader and longer,
reaching the malar below in the Penguin. The premaxillary is comparatively short
and rounded : the Penguins have a quite different type of beak from that in the Alcadae.
The malo-squamosal zygoma is sigmoidally bent, chiefly concave below, not straight as

1 Phil. Trans. 1851, pl. 52. figs. 48-51.