17a ON THE ANATOMY AND AFFINITIES OF 
seven to eleven in number, the huge prehensile claws with their 
curious denticulated edges attached to limbs of great length, the 
shorter swimming limbs with their paddle-like appendage, and 
several semi-oval detached plates which evidently belonged to the 
breast or under side of the animal. Putting all these portions in 
place as nearly as could be determined, we had a huge lobster- 
like crustacean, but only lobster-like in general contour, for in its 
true generic relations it belonged to no existing family of the order. 
Partly phyllopod and partly pzcilopod, in its abdominal segmenta- 
tion macrourous, and in its thoracic apparatus resembling the existing 
Limulus. The Pterygotus could be classed with no living family, and 
was in aspect more like the larve than the adult forms, of any 
‘Crustacea with which we are acquainted. This peculiarity, indeed, 
ran throughout the whole of the Crustacea (and there were several 
new forms he would notice on another occasion) which had hitherto 
been found in this geological horizon,—a horizon that would yet be 
found to be marked peculiarly by its strange Crustacea. From the 
portions he now exhibited to the section, the members could perceive 
at a glance that the restoration by Professor M‘Coy was altogether 
erroneous, and bore scarcely any resemblance to what the creature 
must have been when alive, and acting the part of a scavenger 
along the muddy shores of the Old Red Sandstone seas. The 
figures on the walls (Mr. Page here exhibited what he conceived 
to be a near approach to a complete restoration) would afford some 
idea of the general features of the animal, which he had found 
of all sizes from ten or twelve inches up to full five or six feet 
in length. Such was the Péerygotus, and looking at its complex 
structure, as well as the similar structure of other Crustacea of 
the period, there could be no doubt that no existing classification 
of the order embraced them in its subdivisions. The fact was, that 
the existing Crustacea were by no means well worked out as a group, 
and the discovery of these strange fossil forms rendered the study still 
less perfect.” 
The comparative anatomist acquainted with the labours of Milne 
Edwards, Dana, Bell, Baird, Schaeffer, Darwin, and a host of other 
workers, will hardly be disposed to agree with the opinion expressed 
in the commencement of Mr, Page’s last paragraph, though doubtless 
a good deal remains to be done. In Mr. Page’s reference of the 
Pterygott to a distinct group, he has, as we have seen, been antici- 
pated, and his restoration of their structure is hardly more fortunate 
than that of his predecessors. His “ posterior cephalic or thoracic 
shield” is the epistoma, and has a wholly different place from that 
