Mr. E. Ray Lankester on Scaphaspis and Pteraspis. 191 



minute structure of these shields or cephalic plates is a very peculiar 

 one, having a striated, a cancellous, and a laminate stratum. In the 

 three genera it is beyond all doubt established that the structure is 

 identical, as Dr. Kiinth admits. The same kind of origin must be 

 assigned to the plates of all three genera. Hence, if Pteraspis be 

 the remains of a fish, so are Cyathaspis and Scaphaspis. This posi- 

 tion, I believe, is unassailable, and was admitted by Dr. Kiinth. 

 2nd. A specimen, most carefully figured and described in my Mono- 

 graph, now in my possession, but which I shall shortly place in the 

 British Museum, shows seven rows of rhomboid scales attached (not 

 merely adjacent to) to a portion of the head-shield of a Pteraspis. 

 That these are true scales or lozenges of sculptured calcareous 

 matter is absolutely certain: it is also absolutely certain that the 

 shield is Pteraspidian, and that the scales and shield belong to the 

 same individual organism. This is clear from the figures drawn by 

 Mr. Fielding, and cannot be doubted without charging both him and 

 me with gross misrepresentation. 3rd. The scales are fish-like. I 

 know of no Arthropod, nor any other organism except a Fish, which 

 possesses any structure even remotely representing them. The shells 

 of ChitonidcB and Cirrhipedia are the only animal structures, except 

 the scales of a Ganoid fish (with which they agree exactly), which 

 they could even vaguely suggest. Hence the Pteraspis shield was 

 borne by an organism which bore also scales like those of a fish : 

 that is, a fish or fish-like animal. And what is true of Pteraspis is 

 from paragraph 1 shown to be true of Scaphaspis and Cyathaspis. 

 4th. In figs. 8, 9 of pi. vii. of my Monograph, restorations of the 

 form of the shield of Pteraspis are given, which are not hypothetical 

 or schematic, but simple copies of the parts preserved in various 

 specimens, some nearly perfect, also figured in the work. The form 

 of his shield, and its details as to apertures, processes, etc., agrees 

 with the view that it belongs to a fish most fully. It has not the 

 remotest suggestion of Crustacean affinities about it. Hence again, 

 and by quite independent evidence, we have the piscine nature of 

 Pteraspis indicated. Hence by paragraph 1 we have also additional 

 wan'ant for considering Cyathaspis to be piscine. 



Turning now to Dr. Kiinth's material, consisting of shields un- 

 deniably referable to my Scaphaspis and Cyathaspis, I find — if I 

 may judge from his by no means carefully finished drawings — 

 nothing which can be seriously put in the balance against the above 

 incontestable demonstration of fish-like characters. If Dr. Kiinth's 

 evidence did warrant his inferences as to Crustacean affinities, it 

 could not affect the facts cited above. We should have to regard 

 the Pteraspidians as organisms combining the characters of Fish 

 and of Crustacea. But the evidence offered is really ludicrously 

 insufficient. These shields occur often enough, crowded together 

 in a slab of stone. Dr. Kiinth picks out two shields, accidentally 

 brought into contact with certain most vague and irregular frag- 

 ments placed near them — not by any means attached to them — and 

 upon these raises a theory. The specimen, if we may judge by the 

 figure, cannot really cause a moment's serious doubt in the mind of 



