210 



REPORT ON THE STATE CABINET. 



Fig. 11. 



in observed fragments of the ordinary species of Graptolites. The cel- 

 lules are very minute, and from the frequent ramifications, this would 

 probably always be recognized as a branching species. 



Some of the forms of Dendrograptus have slender spreading branches, 

 and less rigid stems than the typical species, but still retain the angular 

 cellules. From these we pass almost imperceptibly to the slender spread- 

 ing forms which I have termed Callograptus (PI. iv, figs. 13-15) in which 

 there is, apparently, some slight modification in the form of the cellule, 

 and the branches are sometimes united at regular intervals by slender 

 lateral processes. Except for the dark corneous or chitinous textures, 

 these, in their general aspect, might be regarded as slender Brj^ozoans. 

 From these forms there is an almost insensible gradation to the Dicty- 

 ONEMA, in which the branches are connected by lateral bars, at nearly 



regular intervals, and the whole is 

 developed in a funnel-shaped or flabelli- 

 form frond,* with angular cellules on 

 the inner margins of the branches, as 

 in D. retiformis, figure 11. 



There are certain other forms of 

 Graptolites, which, though possessing 

 linear, straight or slightly curving stipes 

 and angular cellules, like the typical 

 species, have yet a different aspect, and 

 do not so naturally fall into the series. 

 Among these we find 

 Graptolithus {Coenograp- 

 ius) cUvergens, figure 12, where the bilateral relation of 

 the parts is still shoAvn, but the celluliferous stipes or 

 branches are arranged on the two sides of a slender 

 rachis, and diverge on each side from what appears to 

 be the centre or initial point. 



Among numerous specimens there are some slight variations of these 

 characters, but not any essential differences. 



Another form, which we know only in small individuals, is illustrated 

 in figures 13-16, enlarged to twice their natural size, which remind one 

 of some forms of the recent Genus Crista.! 



Fig. 1 



* The typical species of the genus are clearly funnel-shaped, and all the others may he so lilce- 

 ■ffise ; but we know some of them only in fragments, of such form as to render it impossible to 

 determine whether the entire frond may have been flabelliform or infundibuliform. 



t Should this form prove not to be the young of G. gracilis, it will require a new designation 



