130 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



genus Dichogrcq^sus, to which it appears properly to belong. Owing, 

 however, to the bad preservation of this as of most of the Skiddaw 

 Graptolites, hardly any distinctions of any value can be di'awn from 

 the minuter characters of the frond ; and the generic position must 

 be mainly determined by the mode of branching. The specimen 

 before me, the only one hitherto discovered, is from the collection 

 of Prof. Harkness, and contains the remains of two individuals. 

 The perfect frond consists of four compound branched stipes, spring- 

 ing from a central funicle ; so that it might be considered a com- 

 pound Tetragrapsus. The length of this central portion, or " vin- 

 culum," is from ^ to ^ of an inch ; and it appears to be really 

 devoid of cellules, thus constituting a true " funicle." It divides 

 at either extremity into two branches ; but I am unable to make 

 out whether these bear cellules or not, and am therefore uncer- 

 tain where the funicle ends and the celluliferous stipes begiu. Each 

 of these four divisions (which are probably parts of the funicle) then 

 divides into two, the branches thus produced repeatedly subdividing in 

 a similar dichotomous manner, at intervals of from ^ to 1 inch, and at 

 angles of from 50° to 60°. The single stipes are monoprionidian, 

 about ^ of an inch in breadth, without any well-marked axis, but with 

 a conspicuous common canal. The cellules are very badly preserved, 

 there being apparently about 16 in the space of an inch ; the 

 denticles are prominent and angular, but are too imperfectly re- 

 tained for further particularization. In one individual, one of the 

 main stipes, -with its subdivisions, attains a length of 7 inches, 

 without showing any signs of a termination ; so that the breadth 

 of the entire frond must have been more than 14 inches. Di- 

 chograpsus multij>lex, from its mode of division, is obviously and 

 closely related to that group of the Quebec Dicliograjpsi which 

 contains Graptolithus jlexilis, G. rigidus, and G. ahnormis of Hall; 

 and as these are devoid of any central disk, it is probable that 

 this species also wanted that appendage. It differs from the above 

 Canadian species in its much greater size, in its more regular 

 dichotomous division, and in the nearer approach apparently made 

 by the cellules to the central portion of the frond. 

 Loc. I^ear Peelwyke, Bassenthwaite. 



Genus Tetkagrapsus, Salter. 



Like the last, this genus was founded by Mr. Salter, but was subse- 

 quently rejected by Prof. HaU, chiefly upon the ground of not being 

 readily applicable to any but perfect specimens. The remarks, how- 

 ever, which I have already made as to the expediency of retaining the 

 genus Dichograpsus apply with equal, if not with greater, force to 

 Tetragrapsus, for which Mr. Salter's definition, with some altera- 

 tion, is quite sufficient. The essential characters of the genus con- 

 sist in the possession of a frond, which is composed of four mono- 

 prionidian simple stipes, arising from a central non-celluliferous 

 funicle, which bifurcates at both ends. The celluliferous branches 

 do not subdivide ; and there may be a central disk or not. Three 



