88 Proceedings of the Royal Physical Soctety. 
to a Marsipobranch affinity. . . . There appears to me no 
inherent objection to referring the animal to a kinship with the 
Hags, merely because its skeleton was superficially calcified, 
especially if Dohrn’s views of the origin of Cyclostomata by 
degradation from a truly gnathostomous type, and if Walcott’s 
‘recently alleged discovery of a Chimeroid notochord in the 
Ordovician strata, should ultimately prove correct.” 
The other writer is Mr Smith Woodward, who has 
furnished some notes regarding this organism, as well as 
a “restored” sketch embodying his idea of its structure. 
Concerning its affinities, he remarks :—“ It seems to possess 
an unpaired nose, lip cartilages in place of functional jaws, 
and no paired limbs; thus agreeing precisely with the 
lampreys and hagfishes, of which the fossil representatives 
have long been sought. Theoretically speaking, allies of these 
limbless Chordata ought to have been a dominant type in 
the late Silurian and early Old Red Sandstone age; and it is 
a well-known law that animals, when dominant, attain to a 
higher degree of development than at any other time in 
their history. It is extremely probable, therefore, that 
Palewospondylus belongs to this interesting category.” 
Mr Woodward, indeed, goes so far as to see, in the head 
of Palawospondylus, “a great broad ring crushed upon the 
anterior part of the skull,’ which “bears an extraordinary 
resemblance to the annular cartilage forming the rim of the 
mouth in the lamprey.” If there is no mistake here, we 
should certainly expect to find other points of correspond- 
ence of an equally interesting character between the skulls 
of Palwospondylus and Petromyzon, and the affinities of the 
former with the living Marsipobranchs must be very much 
closer than I ever imagined them to be when I first hazarded 
the suggestion of such an alliance. 
Since my first notice of Palwospondylus was asta I 
have examined a considerable number of additional speci- 
mens, some of which were collected by myself and my friend 
Mr John Gunn; others, and among these the beautiful 
specimen represented in Pl. I, Fig. 1, I obtained from Mr 
Donald Calder of Thurso. 
1 Natural Science, vol. i., No. 8, October 1892, p. 597, fig. 1. 
