DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. 525 
and forms a curved lobule, which joins that of the antero-parietal at the internal perpen- 
dicular fissure. It, moreover, is in continuity with the extremity of the angular gyrus. 
The third ascending parietal appears as a band sunk within the Sylvian fissure, and 
constitutes the anterior lip of the latter, or becomes what in man has been termed 
supramarginal. Its upper loop embraces the top of the upright Sylvian fissure, a 
descending wedge-shaped turn serving as a division between the latter sulcus and its 
long posterior branch. The continuation of the supramarginal gyrus and lobule is 
equivalent to the angular convolution, which bounded above by the intraparietal 
fissure, below by the 2nd Sylvian parallel fissure and temporal lobes, strikes obliquely 
upwards to the summit of the occipital region. A lobular expansion is manifest 
outside that of the postparietal, a narrow bridge connecting these, and another joining 
it to the posttemporal convolution. 
Temporal and occipital gyrii—The anterotemporal is an inversely U-shaped fold. 
Its short upper limb sinks into the middle of the Sylvian fissure; the longer lower limb 
curves forwards below the lobe, and partly bounds the Sylvian cleft behind. The middle 
temporal gyrus is a single sinuous S-shaped fold which above abruptly ends or dips into 
the post-Sylvian fissure. The posttemporal convolution goes parallel to the latter as 
far as the post-Sylvian sulcus, meantime exhibiting greater tortuosity. Above the mid- 
temporal it doubles or is transformed into a lobule which stretches up to the supra- 
occipital region and is there connected with the occipital gyri. As above mentioned, a 
narrow bridge unites the posttemporal to the angular gyrus, and breaks the upward 
continuity of the post-Sylvian fissure. 
An infraoccipital gyrus of a simple band-like character is well marked behind the 
posttemporal. Mid- and supraoccipital convolutions are less easily defined, or are 
represented by those post upper and inner strips which overhang the cerebellum and 
outwardly blend with the lobular terminations of the posttemporal and angular gyri. 
e. Sulci and Gyri of the inner face—The great marginal convolution extends to 
about opposite the middle of the corpus callosum, has but moderate depth, and is 
broken into several lozenge-shaped folds by short secondary sulci. ‘The calloso-marginal 
fissure is interrupted thrice by upward intrusive folds; nevertheless it can be followed 
to nearly above the splenium. The convolution of the corpus callosum presents a 
lower straightish plication and upper diverticula. A posterior downward loop rounds 
the corpus callosum, forming a callosal lobule in proximity to the upward fold of the 
uncinate gyrus. A second loop above and in front of that mentioned reaches forwards 
and lies subjacent to a third and horizontal loop, representative of a quadrilateral 
lobule. This is bounded behind by a somewhat forward, shelving, internal, per- 
pendicular fissure, which dips into a fold or ridge leading to the relatively large internal 
occipital lobule. The latter lobule has a rounded exterior border approaching close to 
the occipital edge, a marginal occipital sulcus intervening, which sulcus has com- 
munication in front with the internal perpendicular fissure. Inferiorly the internal 
VOL. VIII.—PART Ix. June, 1874. 4D 
