272 REPORT ON THE STATE CABINET. 



that no one of them gives evidence of completeness at the base ; and 

 including the figures of Salter, Harkness and M'Coy, we shall find no 

 better evidence of it. Consider also Mr. Carruthers' description of 

 Cladograptus, where he says " the polypidom, at its origin near the 

 base, is very narrow, being little more than a fine line : as it increases 

 in breadth," etc. Now had this been broken off, when filled with the 

 common body, where it had the width of a fine line, would it not have 

 become less from consequent contraction, and have appeared as if com- 

 plete at its lower extremity 1 When we look at such forms as G. gracilis 

 in the slender attachment of the stipes to the common rachis, could we 

 decide, in their separated condition, whether they were entire bodies, or 

 stolons from a common bodj^'? I do not mean, however, to assert that 

 there are no single mmioprionidian stipes which are complete in themselves. 

 I am willing to reassert here what I have before said, that in the 

 separated portions of the Graptolites we cannot distinguish between 

 DiDYMOGRAPTUS, Tetragraptus and DiCHOGRAPTUs ; and in regard to the 

 latter term, if it is to be brought into use, we have a right to some expia- 

 tion of its meaning and its limits. In the figure first given by Mr. 

 Salter in the Geologist (1861), where the name was proposed we have a 

 properly branching form, not very dissimilar from G. milesi of this paper, 

 but without a disc; and no allusion is made to a disc. In 1863,* Mr. 

 Salter gives a figure o^ Dichngrapsus aranea of Salter, a form with eight 

 simple celluliferous stipes; and also "fig. 10, Dichograpsiis Salter with 

 its corneous cup (fromLoGAN)." Fig. 11, Dichograpsiis sedgwicJdis another 

 species with eight simple stipes. At that time, it does not appear that Mr. 

 Salter had seen a British specimen with a central coi'neous disc. The addi- 

 tion of the disc to Dichograpsus was a subsequent idea, and the adoption of 

 such forms as G. aranea and G. seclgivicld as the types of his genus by Mr. 

 Salter, leaves out the really branching forms, like the diagram in the 

 Geologist for which the name was first proposed. If separation is to be 

 made on such grounds as these, a farther one must be adopted ; and the 

 Genus Dichograpsus, which now includes three types, must be restricted 

 to the types D. aranea and D. sedgivicki. This arrangement will leave 

 those forms with the central corneous discs to form a new genus, for 

 which I propose the name Loganograpttjs. Those which are repeatedly 

 dichotomous, like G. flexilis, will constitute a third genus ; for notwith- 

 standing that Mr. Salter says the Dichograpsus " is doubly branched 



* Quart. Jour. Gaol. Society, Vol. xix, p. 137. 



