Contribution to Knowledye of Paleeospondylus Gunni. 517 
of this specimen, magnified thirteen diameters, The differ- 
entiation of the vertebral centra and arches is in this case 
obscure, but the spinous processes are extremely distinct, and 
the dichotomisation of those on the neural side of the axis, 
which are also the longer, is seen with the greatest ease 
under a low power of the compound microscope. Not the 
smallest trace of transverse segmentation can be observed in 
these rods, or in their dichotomous divisions. 
AFFINITIES. 
In my first notice of Palwospondylus (1) I suggested the 
idea of a Marsipobranch affinity, an idea which, having been 
favourably received by Professor Howes and Mr Smith 
Woodward (3 and 4), I sought to develop still further in my 
second paper (5). And though the examination of the most 
recently obtained material has modified as well as added to 
our ideas on the subject, the result, instead of weakening 
the probability of the alliance of Paleospondylus with the 
Marsipobranchs, tends to strengthen it up to what one feels 
tempted to consider a tolerably close approximation to 
certainty. 
Sir J. W. Dawson has, however, expressed himself in 
favour of a different interpretation of Palwospondylus, after 
an examination of specimens forwarded to him by Mr J. 
Reid, Blairgowrie. It must, however, be noted that the work 
(6) in which he alludes to the matter had been sent to press 
before he had the opportunity of seeing my second paper. 
He says: “It is a little creature, an inch to two inches in 
length, destitute or nearly destitute of bony covering, having 
a head which suggests the presence of external gills, large 
eyes, and even elongated nasal bones. . . . One cannot 
look at it without the suggestion occurring of some of the 
smaller snake-like Batrachians of the Carboniferous and 
Permian; and I should not be surprised if it should come to 
be regarded either as a forerunner of the Batrachians or as a 
primitive Tadpole.” 
These observations are accompanied by a drawing, which 
is original as regards the head, though-evidently taken from 
