372 Graptolites, 



from Nimmo's notice that he had ever seen a graptolite, and 

 his absurd conjectures may be excused, while the folly of its 

 publication evidently rests with the then editor of the Calcutta 

 Journal. M'Crady and Boeck, on the other hand, came to 

 their conclusions after examining specimens ; but the descrip- 

 tions already given of the structure and general form of these 

 fossils render it unnecessary to refute such notions. 



Walch is the first naturalist who recognized the animal 

 nature of graptolites. In his work on the fossils of Knorr's 

 Museum, he figures two species, which he describes as small 

 toothed orthoceratites. The one is most probably G. priodon, 

 preserved in the round, represented externally in one figure, 

 and in section in the other. Geinitz has mistaken the dark- 

 coloured divisions between the cells shown on the surface of 

 the polished slab for specimens of Rastrites peregrinus. The 

 other species figured is G. convolutus. Walch's opinion that 

 they were minute cephalopods was entertained by many 

 naturalists, among others by Wahlenberg and Schlotheim. 

 Barrande at length set the matter at rest by clearly showing 

 that they could not structurally belong to this group, but must 

 be zoophytes. 



Nilsson, the venerable Swedish naturalist, was the first to 

 suggest their true affinities. Some thirty years ago he was 

 engaged in the study of these fossils, and published an abstract 

 in anticipation of a complete memoir, which he has never 

 given to the world. At that time the classification of zoophytes 

 was very imperfect, and in the family Ceratophyta, to which he 

 referred them, were included a number of organisms now 

 known to have no affinity with each other. Beck, in a note in 

 Murchison's Silurian System (1839), refers them to the neigh- 

 bourhood of Pennatula, and he has been followed by Barrande 

 and others. The possession of a solid axis, and of a free 

 polypary^ are the points chiefly relied on by those who main- 

 tain this view. M'Coy thinks they were Sertularians, because 

 the form of their horny polypary and the polype cells were the 

 same as in that family. Salter, Greene, and others would raise 

 them much higher in the scale by placing them amongst the 

 Polyzoa. 



In trying to estimate, if it bo possible, which of these 

 opinions is the most accurate, it will be necessary to ask first, 

 what are the characters to which we have access in graptolites 

 that are most important in throwing light on their systematic 

 position. Some make the general form of importance ; but, 

 on the one hand, this is one of the most variable characters in 

 the same family, and on the other, it is one which repeats itself 

 in very different families. It would be impossible to dis- 

 tinguish between the Hydrozoa and the Polyzoa from general 



