HISTORY OF RESEARCH. cxiii 



being new. The following are described : Bastrites peregrinus, R. hybridus, 



Monograptus gregariits, M. limatulus, M. leptotheca, M. crenulatus, M. contiiiens, 



M. priodon (Tornquist discusses and criticises the view of Jaekel as to the 



structure of the theca in this species), M. cygneus, M. cultellus, M. lobiferus, 



M. c/r. BecJci, M. singularis, M. sartorius, M. ansulosus, M. cfr. dextrorsus, 



M. exiguus, M. nodifer, M. runcinatus, M. Sedgwichi, M. convolutus, M. spiralis, 



var. subconicus, M. turriculatus, M. discus, M. proteus, M. flagellaris. In all 



the illustrations great attention is paid to the correct figuring of the proximal end. 



1892. The proposal of Moberg to adopt Hopkinson's and 



lornquist, Lapworth's suggested name of Dictyograptus in place of 



•i- I && „ r-i , Dictyonema was discussed and criticised by Tornquist in 

 syuouymitraga, ' Greol. J . . 



Foreu Fork ' bd xiv 1892. He considers that the fact that "Dictyonema" is an 



old-established name for a genus of plants is not a sufficient 

 reason for its rejection. 



In 1892 (?) James published the second part of his 



j ames Manual on the Pala3ontology of the Cincinnati Group dealing 



" Manual of Palseon- with the Ccelenterata. 



tology of the Cincinnati Classification. — James considers that in the sub - class 



Group, pt. 2, Hydroida there is only one order — the Thecaphora — and that 



this includes the two genera Dendrograptus and Dictyonema. 



Under the genus Dendrograptus (which according to James includes Buthotrephis, 



Hall, pars, and Psilophyton, Lesqx.) he describes D. gracillimuni, Lesqx., D. tenui- 



ramosus. The genus also includes D. arbuscuhim, Ulrich (= D. irregulare, Hall). 



According to the author the sub-class Graptoloidea comprises seven genera : 

 (1) Graptolithvs ; (2) Diplograptas, including the two species D. spimdosus and D. 

 Whitfieldii ; (3) Gllmacograptus with its species G. typicalis and G. bicomis ; (4) 

 Dicranograptus, type D. ramosvs; (5) Megalograptus (j\L Welchi being entirely distinct 

 from any other known Graptolite) ; (6) Inocaulis; and (7) Dawsonia (LocJccia), D. 

 siliquaria. 



In 1892 Jahn published a preliminary report of his 



T 1 ' investigations among the Dendroidea of the Silurian Rocks 



" Vorli'iufio-er Bericht °^ Bohemia. He discusses the history of our knowledge of 



iiber die Dendroiden the genus Dictyonema up to the year 1875, but ignores the 



des bolnnisclien Silur," more recent work. He considers that many species have 



' K. Akad. Wiss. Wien, i Jeen mc i ut | et [ inu ] el . this genus which really belong to other 



Matheni. Naturw. . 



„, , , , . , ., „ genera, and he suggests that Desmoqraptus, regarded by 

 Classe, bd. ci, heft 7. ° btD J ± t> J 



Hopkinson and Lapworth as a sub-genus of Dictyonema, 

 should be regarded as a distinct genus. He also proposes' a new genus — 

 Damesograptus. Jahn names eight new species of Dendroidea, mainly from 

 Stage E. e. 2 in Bohemia, but gives no descriptions or figures. These are 

 Gallograptus tenuissimus, Gallog. bohemicus, G alloy, palmeus, Desmograptus 



<1 



