Ixviii BRITISH GRAPTOLITES. 



to Heidenhain, occurs without associates in a harder dark limestone), and ((>) M.sp. 

 (This last was afterwards named by Jaekel M. micropoma.) The age of the beds 

 from which these erratics must have been derived is from this record of Graptolites 

 now known to be Lower Ludlow. 



He records from rocks somewhat different in character, and therefore probably 

 from another geological horizon, I>. palmeus, var. tenuis and 1>. pristis ?, and gives 

 descriptions of them. 



During the same year Nicholson described and figured 



186'* 

 jy- i 7 ' several new species, and one new genus of Graptolites 



" On Some New from the Lake District. The new genus, which he names 



Species of Graptolites," Trigonograptus (1) ( T. ensiformis type), he regards as inter- 

 ' Ann. Mag. of Nat. mediate between Betiolites and Diplograptus. A form which 

 Hist.,' ser. 4, vol. iv. he ^ ere denominates (2) Dichograpsus fragilis was afterwards 

 made by himself the type of a new genus Trichograptns. Other new species 

 described and figured by him in this paper are (3) Dichograptus? annulatus, 

 (-1) Diplog. Hopkinsoni (= Crijplograptiis), (5) I', armatus (? Glossograptus), (0) 

 D. Hughesi, (7) D. sinuatus, (8) D. bimucronatus, (9) D. insectiformis, (10) 

 Glimacog. innotatus, (11) C. tuberculatum, (12) Gr. argenteus, (13) Didymog. 

 affinis, and (14) D. fasciculatus. He also re-figures (15) D. vesiculosus. 



jago The same year Linnarsson recognised two distinct 



Linnarsson, graptolite horizons in Sweden: (1) the Lower Graptolite 



'• Oin Vestergotlands Shales, with Phj/llograptus, Didymograpsus, etc. (the equivalents 



Cambriska och Silu- f th0 Skiddaw Slates), and (2) the Upper Graptolite Shales, 



riska Aflaeringer. ■,■■ n , 7 -,, . ,• , ,, , ■, . 7) , • 7 • , 



with (rraptoiitlius, IJipiograpsus, Liastrites, and lieAiolites, con- 

 taining fossils similar to those in South Scotland. As the latter occur above the 

 Brachiopod Shales (Caradoc) he thinks that the Llandeilo age of the Scotch beds 

 (Murchison) is probably incorrect. 



In a paper read before the Quekett Microscopical Club 



„ , . Hopkinson o-ave a generalised account of the British Grapto- 



Hopkmson, roe i 



" On British Grapto- lites. The history of research among the Graptolites is briefly 



lites," 'Journ. Quekett dealt with, and their structure is described in some detail. 



Microscopical Club,' He adopts throughout the Hydrozoal nomenclature first 



employed by Carruthers, each term being carefully defined. 



He accepts Carruthers' classification for the most part, but he places all true 



Graptolites in the single order of the Graptolitidse, and regards Carruthers' four 



classificatory sections as "suit-orders " or " families," which he names respectively 



Monoprionidse, Diprionidas, Monodiprionidae, and Tetraprionidas. 



In the family Diprionidas, Hopkinson suggests a new genus, Cephalograptus, 

 to include the single species D. cometa , Gein. He figures (1) Raxtrite-i peregvinus, 

 (2) Gr. pn'odon, (3) Gr. Bisingeri, (4) Gr. Sedgwickii, (5) Gyrtog. Murchiscni', 

 (C) Didymog. Murchi«oni, (7) Tetrag. Irycmoides, (8) Dichog. octohrachiatus. He 



