^0 Carruthers — On Graptolites. 



^- — Note on the Systematic Position of Graptolites, and on 



THEIR SUPPOSED OvARIAN VeSICLES. 

 By "Wm. Carruthers, F.L.S. 



ANY observations which can throw light on the systematic 

 position of the Graptolitidce are of great importance. That 

 these anomalous fossils are Zoophytes, in the wide sense of the term, is 

 almost universally conceded ; the difficulty is in determining whether 

 they are coelenterate or molluscoid. Those who have described the 

 members of the family have almost invariably considered them to be 

 hydrozoa, and it must be allowed that in general aspect they very 

 much resemble Plumularia and Sertularia. But when their structure 

 is examined it will be found that they widely differ from any known 

 hydro25oon, and especially in that the entire polypidom is composed 

 of the^ different polype-cells, without any distinct common canal. 

 Sometimes the polypes rise from a common substance which extends 

 along the whole of the celluliferous portion of the organism, but 

 there is no constriction or septum at the base of the cells, cutting off 

 this common substance from the individual polypes. This is the 

 structure of GraptoUtus priodon, Bronn. In other species the walls 

 of each cell seem to be continued to the solid axis, as is the case 

 most probably in Graptolitus Sagittarius, L. and certainly in some of 

 the species with a double series of cells, as Diplograpsus folium, His. 

 B. pristis, His. and D. cometa, Gein. The mouths of the cells are 

 frequently furnished with one or more long spines, as in some species 

 of Bastrites, and in Diplograpsus pristis, His. In these characters 

 the graptolites show a greater affinity with the polyzoa. Compare 

 the genera Scruparia and Bicellaria. But there are some peculiarities 

 which do not well agree with the living forms of either section of 

 zoophytes. Among these may be mentioned first the prolongation 

 of the solid axis in both the unilateral and bilateral forms beyond 

 the celluliferous portion in the newer part of the polypidom, and 

 then their free polypidom s, for neither the spines which terminate 

 the older jDortion of some species of Diplograpsus nor the slender 

 base of Dendrograptus linearis, Car., could be radicles, and the species 

 of the genus Graptolitus have no indications of a hydrorhiza from 

 the older extremity. 



Any information as to the method of reproduction would greatly 

 assist in forming an estimate of their alfinities. In the November 

 number of this journal (Vol. III. p. 488), Mr. H. A. Nicholson drew 

 attention to some minute organisms from the graptolite shales of 

 Moffat, which he supposes to be the ovarian vesicles of Graptolites. 

 I have in my collection two or three distinct forms of these capsules, 

 and I have considered (perhaps wrongly) the fossils figured by Mr. W. 

 H. Baily in the explanation to sheet 133 of the Irish Survey, p. 12, 

 as another form. Thinking they might be ovi-sacs, I have for many 

 years been carefully looking out in my quarry ings in the Moffat 

 shales for any indication of the connection between the organisms 

 and the graptolites. In shales where every fossil is almost always 

 compressed to a mere film, and the remains are confusedly scattered 



