130 Anatomy of Sperm Whale Fotus 
according both to my own measurements and to those of Mr. Chubb 
(in litt.). This being the case it is remarkable perhaps to note in 
Prof. Kiikenthal’s figure a more strongly marked likeness to the usual 
dolphin form as evidenced not only by the proportions of head to 
trunk but by the form of the head. This likeness is duly noted by 
the author. One would imagine that likenesses to the more generalised 
Cetacean shape and proportions would be more apparent in the 
younger and die away in the older fetus. This resemblance is, 
however, as I believe, deceptive, and meiely due to the state of 
preservation of the actual specimen. It will be noted that it les 
mainly in the form of the head ; there is in Prof. Kiikenthal’s embryo 
more of a snout as contrasting with the rest of the head than in both 
of the smaller fcetus described in the present paper, and in the earlier 
one examined by myself. The line of the head at first rises abruptly 
as in the three younger fetus but then forms a sloping forehead 
gradually rising to its greatest altitude. In the two largest foetus in 
my possession, and even in the youngest to some extent, there is not 
so marked a slope. The outline is more that of the adult Cachalot. 
I imagine, however, from my examination of my own feetus that this 
is simply due to the collapse, by contraction, of the oil containing 
upper half of the head, more distinct in the older than in the younger 
specimens. 
Tue Heap. 
Of the two foetus which I describe in the present communication 
figures are given on Plate XXIII which may be compared with that 
of the older fcetus formerly described by me* and with that of 
Kiikenthal just referred to.; Several differences in general outline 
are at once apparent on a comparison of these several figures. The 
younger fcetus have the head either slightly bent downwards or very 
markedly so in the youngest of the series. The characteristic form of 
the adult Cetacean, already arrived at in the feetus measuring 20 
inches, and naturally also in the larger one studied by Prof. Kukenthal, 
is not quite established in the two younger specimens, and least of all 
in the youngest, where the long axis of the head is at right angles, or 
nearly so, to the long axis of the trunk. It is important to notice, 
however, how very early this coincidence of the long axis of the head 
and trunk is established in this Cetacean. In whales generally the 
* This Journal, t.c., Pl. VIII, fig. 1. 
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