BRITISH GRAPTOLITES. 



1881. 



Holm . 



" Tveime liya sliiglen 



af familjen Dichograp- 



tidse," ' Ofvers. K. 



Yetenskaps A lead. Fiir- 



handl.,' no. 9. 



Two new genera were founded by Holm in 1881 for 



certain forms of Dichograptida? with four primary stipes : 



Holograptus. His genus (1) (type II. expansus) includes 



those species in which the four primary stipes branch 



irregularly and on both sides. The type species occurs in 



the Phyllograptus shales of Vestergotland. 



In his genus (2) Trochograptus (type T. diffusus) the 



four primary stipes give off branches on one side only at fairly regular intervals, 



and these may branch again in their turn. 



Holm shows that the so-called " funicle " bears cells in T. diffusus, and is not 



non-celluliferous, as originally supposed. 



1881. In 1881 Holm described a third genus, namely, Ptero- 



H° lm < graptus, with its species P. elegans. 



" Pt erogrcuptus, ett nytt TT ,. ,, ,. - ,, ,, VJ . 



He again discusses the question ot the ceJluhterous or 



non-celluliferous character of the " funicle " in Graptolites. 

 He thinks it not improbable that the "funicle" will prove to be 

 always celluliferous, even in the case of Coenograptus gracilis. 



Barrois notices the occurrence of Monog. colonus, M. Sedg- 

 wichii, M. priodon, and M. Hisingeri in the Ampelite Shales 

 of Crozon. A previous record of the existence of Graptolites 

 at this horizon had been made by M. Guillier. 



In 1881 Keeping made known the existence of various 

 graptolitiferous horizons in the Silurian of Central Wales, 

 and utilised the Graptolites for the purpose of working out 

 the geological succession in that region. 



In addition to the Rhabdophora collected by him, Keeping 

 found a number of Cladophora, most of them new to science. 



In an appendix to this paper, Lapworth described and 

 figured seven new species of Cladophora discovered by 

 Keeping. These are : Didyonema venustum, I), delicatulum, 

 I), corrugatellum, Calyptograptus ? plumosus, 0. ? digitatus, 

 Acantlt,ogr<tj>tiis ramosus, and Odontocaulis Keepingii. 



A new genus Odontocaulis is also described and figured. 



Brogger, in a classic work on " Die Silurischen Etagen 2 

 und 3," described and figured two new species of Bryograptus 

 from Norway : Bryograptus ramosus and B. retroflexus. He 

 also re-figured Kjerulf's Qrapt. tenuis (Bryog. Kjerulfi, 

 Lapw.). 

 figured Norwegian specimens of Dictyograptus flabelliformis 



graptolitsliigte," 

 ' Ofvers. K. Vetenskaps 

 Akad. Forhandl.,' no. 4. 



1881. 

 Barrois, 



" Sur le Terrain Silu- 

 rien superieur de la 



presqu'ile de Crozon," 



' Ann. Soc. Gcol. du 



Nord,' vol. vii. 



1881. 

 Keeping, 

 " The Geology of Cen- 

 tral Wales," ' Quart, 

 Journ. Ceol. Soc.,' 

 vol. xxxvii. 



1881. 



LapvjortJi, 



Ibid. Appendix " On 



some New Species of 



Cladophora," ' Quart, 



Journ. Geol. Soc.,' 



vol. xxxvii. 



1882. 



Brogger, 



' Die Silurischen 



Etagen 2 und 3.' 



Brogger also 



