OE THE AMEKICAN PTEEASPIDIAX, PAL^ASPIS. 545 



III. CONTEOYEESY Al^D E-ESTJLTS. HoLASPIS, LaNKESTEE. 



The very peculiar view advanced by Kunth found, as might have 

 been expected, no favour at the hands of palaeontologists, and on 

 the opposite side the field was at once taken, in the ' Geological 

 Magazine ' and in the ' Transactions of the Imperial Russian Minera- 

 logical Society,' by Magister Fr. Schmidt, of St. Petersburg,^ who 

 with much acuteness saw immediately the strength and the weak- 

 ness of Kunth's position, and, while denying the crustacean 

 affinity of his fossil as altogether untenable, maintained and 

 extended his conclusion that the two shields found in juxtaposition 

 really belonged to the same animal, and that this animal was no 

 other than Cyathaspis, as indicated by the dorsal plate. He there- 

 fore fully agreed with Kunth in denying the independent existence 

 of Scapliaspis as a genus, and followed him in assigning its various 

 forms to the different species of Pteraspis and of Cyathaspis with 

 which it was usually found in company. He thus took ground 

 considerably in advance of all previous writers on these fishes, and 

 to him is fairly due the honour of first announcing what is 

 doubtless the true nature of these peculiar fossils. Instead of the 

 rolled-up trilobite of Kunth, Schmidt presented us with an armour- 

 clad fish possessing both dorsal and ventral plates, whereas 

 previously these creatures had been supposed to be protected only 

 above and to be defenceless below. Schmidt further pointed out, 

 in confirmation of his view, the fact that the Devonian fishes were 

 doubly armed in the same manner as his Pteraspidians, and 

 adduced Coccosteus as an example in support. The value of this 

 argument was great, and must be felt by every student of these 

 ancient fossils. But it should, at the same time, be borne in mind 

 that among all the thousands of specimens that had come to light, 

 Kunth's Cyathaspis integer (integra) ^ alone suggested and supported 

 the new view, and had it not been for the excellent state of its 

 preservation, in a smooth hard shale, palaeontologists would have 

 been slow to admit so large a conclusion from so small a premiss. 

 Eut the evidence was so clear and strong that, as Schmidt says, 

 it was useless to attempt to invalidate it.^ 



^ Geol. Mag. for 1873, pp, 152, 330, and Verhaudl, der k. russisch. mineralog. 

 Gesellsch. fiir 1873, p. 132, &c. 



^ It is worthy of remark how uniformly writers on this subject have 

 followed the earlier authors in the error of using these generic terms as 

 masculine nouns. Agassiz seems to have led the way ; consequently nearly all 

 the specific names have been wrongly formed. A few only have appeared in 

 the feminine gender. After remaining in this confusion and error for half a 

 century, it is refreshing to a classical eye to see the needed amendments intro- 

 duced in the Brit. Mus. ' Catalogue of Possil Fishes ' by Mr. A. Smith 

 Woodward. 



^ With regard to the statement of Magister Schmidt, that he has discovered 

 true bone lacuna in the superficial layer of Pteraspis Kneri (Geol. Mag. for 

 1873, p. 330), thereby breaking down the distinction drawn by Lankester between 

 his Osteostracans and Heterostracans, I can only remark that, after the most 

 careful examination of my slides, I have been quite unable to find anything 

 resembling them in Palaaspis, whose shield consists outwardly of a uniformly 

 dense layer of calcareous material enclosing the tubules, but nothing else. 



