The papillae of the skin are about 0"*04 in length, and at their bases there is
a deposit of dark pigment, hut the layer at their ends is colourless. They appear
to he generally distributed and not arranged in lines as in Tlatanista.
The fibrous layer of the skin is 07,45 in thickness.
Tabular view o f body and visceral measurements o f the foetus of
Orcella brevirostris.
From tip o f snout to notch of tail, in straight l i n e .......................................................... 33*75
„ similar points following curve of back, alongside o f dorsal fin . . . . . 36*25
„ tip of snout to angle of mouth, in straight line . . . . . . . . 2*25
From tip o f snout to anterior margin of blow-hole following the ourve . . . '. . 5*00
From tip of snout to base of pectoral flipper . . . . . . . . . » * 7'75
Girth o f the flipper at its b a s e .................................................................................................. 4*50
Pectoral flipper taken along its anterior border .............................................. S'OO
From tip o f snout to anterior base of dorsal fin, in straight line . . . . . - . 18*00
From tip of snout to dorsal fin, following curve of h a c k ................................................. 20*00
Distance from the snout to the umbilicus . ’ . . . . . . . . . . 16*75
From the nmbilicus to the generative o r i f i c e ...........................................................................4*50
Length o f external margin of caudal fin - . . . . . . .. . . .. . 7*75
Length of internal margin of caudal fin, from base of notch! . . . . . . . 5*25
Girth of head, at the blow-hole ....................................................................................15*75
Circumference halfway between blow-hole and anterior border . . . . . . 16*75
Girth of body behind base o f pectoral fin ..................................................................... . 15*75
„ „ at the umbilicus . . . • • . • • . . . ' . 17*50
„ at the root of the tail . 4*75
Depth through tail, half-way between anus and root of fin . . 3*50
Total length of the i n t e s t i n e s ..............................................................................................................271*00
The length o f the small intestine . . . . . . . , . . 232*00
The length of the large in te stin e . 39*00
General remarks on the skeleton.—The number of vertebrae appears to be
subject to little variation, 63 being the maximum in either species and 62 the
minimum. The ribs attached to the vertebrae are generally 12 in number, but
another pair may occur. In instances with the normal number of vertebral ribs,
two pairs of floating ribs may be present, and in those animals with 13 true ribs one
pair of floating ribs may be found.
In the foetus of O. brevirostris and in the adult male of O. Jkminalis, the position
of the pelvic bones was ascertained. In the former they lay between the 35th
and 36th vertebrae,—that is, between two vertebrae bearing well-developed chevron
bones, and anterior to which was the 34th vertebra, with its chevron bones attached
also to the 35th vertebra. In O. Jktminalis, the greater part of the bones lay below
the 36th vertebra, but their anterior ends were opposite to the hinder part of the
body of the 35th. The chevron bones in this species also commenced between
the 34th and 35th vertebrae. If the vertebrae opposite the pelvic bones are sacral,
it is evident that in this genus, at least, the first chevron bones do not indicate the
beginning of the caudal vertebrae properly so called. In Grampus rissoarms a
similar relationship subsists between the pelvic and chevron bones, the latter occurring
before the anterior ends of the former. If the two vertebrae lying above the
pelvic bones are regarded as sacral, the vertebral formula of this genus is as follows:
C. 7, D. 12 or D. 13, L. 14 or L. 13, S. 2, C. 27 or 28 == 62 or 63.
In an adult male 0. fltmmalis, with 13 vertebral ribs, in which the vertebral
segments had never been separated, these respective regions of the vertebral column
had the following measurements : C. 3"*90,1). 18"-80, L. 16"*80, S. 2"*50, and C. 25"*75
= 67"-75, whilst in an adult gravid female of 0. brevirostris with 12 ribs, but which
had had the intervertebral substance removed, the different portions of the column
were as follows: C. 3"'50, D. 14"*75, L. 16"'50, S. 2", and the caudal 26"-90 = 63"*65.
In the former of these specimens the total length of the skull was 12" and in the
latter ll" -75.
Vertebral cohmn.—The first two cervical vertebrae of this genus are the only two
segments which amalgamate with one another. Union, takes place at an early age,
but the amalgamation of the neural arches is never complete, as they are partially
separated from each other by an incision which runs upwards for some distance from
the upper margin of the intervertebral. foramen. This incision is also prolonged
downwards from the inferior border of the foramen, behind the posterior borders of
the facet for the occipital, and is partially prolonged outwards, to the base of the
transverse processes of the axis. The. neural lamina of the 1st vertebra is broad
and strong, but that of the 2nd Vertebra is feeble. The arch between the posterior
zygapophyses of the 2nd vertebra, as indicated by the incision, is of considerable
breadth as compared with those behind it. The combined arches of the 1st and 2nd
vertebrse send up a strong bifurcate spinous process, having behind it a short longitudinal
ridge. The transverse process of the 1st vertebra is a large nodule directed
somewhat backwards and separated by a deep notch from the longer, more pointed,
and backwardly directed transverse process of the axis. The antero-posterior length
of the bones inferiorly is about I"-25, whilst the longitudinal extension of all the
other cervicals together does not exceed 2"*25. The body of the 3rd vertebra has
an antero-posterior thickness of 0"'35, but those behind it manifest a slight increase
to the 6th, whilst in the 7th there is a more marked thickening.
The neural arches of the other cervical vertebrse are moderately high, and
highest and most peaked in the 3rd, 4th, and 5th, the arches of the 6th and 7th
being lower, but having more lateral expansion. The laminse are somewhat feeble,
and occasionally the lamina of one side does not unite with its fellow, and hence
there is only the feeblest trace of a spinous process. In the gravid female the 3rd
7th cervical and 1st dorsal present this feature. The superior transverse process
of the 3rd vertebra is well developed, dilated at its extremity and with a very slight
backward tendency. In the 4th cervical vertebra the process is much reduced in
size, and a forwardly bent inferior process appears, which is much more strongly
developed in the 5th, and is elevated in position on the 6th, in which it can be merely
traced. The upper transverse process is lost on the 5th vertebra, but on the 6th
segment a small upper transverse process appears, and in the 7th it is prominent
on the under surface of the bodies of the 4th and 5th vertebrse; there are two nodular
hypapophyses and an azygos process on the 6th and 7th. Erom these facts it is evident
D 3