270 



REPORT ON THE STATE CABINET. 



where the cellules are similar in form. Such a disposition of the generic 

 terms will satisfy the claims of Profs. M'Coy and Geinitz, each one having 

 in his proposed genus included the two groups of species.* 



In 1858, Mr. Carruthers, without knowledge of Prof. Geinitz's Genus 

 Cladograptus, proposed the same name for a form of graptolite found in 

 the shales of Dumfriesshire. In the typical species, the zoophyte is 

 described as dividing, from a short and slender base, " into two stems, 

 each supporting the cells on their upper sides." " Branches are given off 

 at irregular intervals from these principal stems." In the Intellectual 

 Observer (No. Ixv, 1867), Mr. Carruthers has given the following descrip- 

 tion of the genus : 



" Cladograpsus, Car. Polypary compouud ; growing bilaterally from the 

 primary point ; irregularly and repeatedly branching and rebranching, and 

 without a central disc." 



The original figure illustrating Cladograptus linearis {Annals 6f Mag. 

 of Nat. History) , shows it to be a fossil belonging to the group of G. gra- 

 cilis. Hall, and the figure of the same in the Intellectual Observer shows 

 less distinctly the same characters. The form is not branching and 

 rebranching in the ordinary acceptation of that term (or by dichotomizing), 

 as is clearly enough shown in the figures of Mr. Carruthers. In the 

 figure first cited, the two main parts diverge on two sides from an initial 

 point, and the divisions on one of these parts or branches rise at regular 

 intervals from one side of the common rachis. In the specimen figured, 

 the stipes or offshoots are in two pairs and at equal distances from each 



other, the intervening space being 

 about three times as great as be- 

 tween the individuals of each pair, 

 and probably indicating the place 

 where two others have been broken 

 off. In the American species of this 

 type, there are no cellules on the 

 principal rachis, except towards 

 the distal extremeties of the two 

 parts, and beyond all the subdivisions, which are usually from one side 

 only. 



* I have heretofore used the term Didymograptvs in its appHcation to such forms as G. murchi- 

 soni, forgetting the original extent of its apphcation by Prof. M'Coy; and it is only since the 

 preceding pages have been in type, that on re-reading the remarks of the latter in the paragi-aph 

 cited, I have become more fully impressed with the necessity for some revision of the terms in 

 their application to species. 



Cladograptus linearis, Carruthers. 



