HISTORY OF RESEARCH. 



cxli 



1897. 



Files, 



" The Sub-genera 



Petaloijraptus and 



Cephalograptus," 



' Quart. Journ. Geol. 



Soc.,' vol. liii. 



In 1897 Elles published a paper on the " Sub-genera 

 Petalograptus and Gephalographis" in which she adduced 

 evidences that these sub-genera are quite distinct, and readily 

 distinguished the one from the other. She worked out care- 

 fully the structure of the various species belonging to the 

 sub-genera, especially that of the proximal end, showing that 

 it differs in important particulars in the two groups. 

 From her study of these species she concludes that the Petalograpti have been 

 derived from Orthograptus foliaceus through 0. truncatus, and the CepJialograpti 

 direct from the Petalograpti, Gephalograptus petalum being the intermediate form. 

 Description of Species. — The following species are re-described in detail and 

 re-figured, Pelalog. folium, P. palmeus, var. latus, var. tenuis, and var. ovato- 

 elongatus, P. ovatus, Cephalog. cometa, and two new species, P. minor and C. 

 petalum. 



In this year also Wiman gave a further account of his 

 extended researches on the structure of the Graptolites 

 describing and figuring a large series of cross-sections which 

 he had made of some Graptolites from Wisby in Gothland 

 preserved in silicified limestone. 



He figures a good specimen of Dictyonema cavernosum 

 provided with stolons, one of Dictyonerna (?) tuberosum and 

 one of Glimacograptus. Other forms dealt with are isolated specimens of 

 Dendroidea, which, however, he does not attempt to refer to definite species. 



In a paper read before the Durham Philosophical Society 

 A. Meek summarised the researches of Holm and Ruedemann 

 respecting the structure and mode of growth of the Grapto- 

 lites. 



He lays stress on the supposed absence of a virgula in the 

 Dichograptidge, and suggests that as they " do not seem to 

 have possessed a means of fixing themselves," "it must be supposed that they 

 had the power of movement and temporary attachment with whatever the living 

 contents of the thecas provided." Forms like Phyllograptus he thinks were 

 " purely crawling forms — say by means of tentacles or pseudopodia." 



He tentatively suggests that the presence or absence of a virgula might form 

 the basis of a new classification. 



1893. In 1898 T. S. Hall made a further contribution to the 



Hall, T. b., graptolitic fauna of the Lancefield Beds, Victoria, which con- 



' Victorian Graptolites,' 



1897. 



Wiman, 



" Ueber den Bau einiger 



Gotlaudischen Grapto- 



liten," 'Bull. Geol. 



Inst. Upsala,' vol. iii, 



art. no. 10. 



1898. 



Meek, A., 



" On Graptolites," 



' Proc. Univ. Durham 



Phil. Soc.,' vol. i, pt. 2. 



part ii, " Graptolites of 

 the Lancefield Beds," 

 ' Proc. Roy. Soc. Vic- 

 toria,' n.s., vol. xi, pt. 2. 



firmed his original views that they underlie the Tetragraptus 

 fruticosus zone. 



Description of Species. — He describes and figures a 

 number of new species of Graptolites, including Bryograptus 



