16 Dr. 0. Herrmann — On the DichograpUdce — 



e. Type Diclymograptus affinis, Nich. 



21. Diclymograptus affinis, Nich., Hopk. and Lapw., Tornquist. 

 Angle of divergence 90°-150°. 



Skiddaw Slates, N. England ; Upper Arenig, Wales ; doubtfully 

 in Phyllograptus-shales, Dalecarlia. 



22. Diclymograptus filiformis, Tullb., Lapw., Brb'gg. 

 Tetragraptus-zone, Skane ; Phyllograptus-shales, Norway. 



23. Diclymograptus Nicholsoni, Lapw., Hopk. and Lapw. 



D. serratulus, Nich. 

 Upper Arenig, Wales ; upper part of Skiddaw Slates, N. England ; 

 doubtfully in Phyllograptus-shales, Norway. 



24. Diclymograptus pusillus, Tullb., Lapw., Brogger. 

 Angle of divergence 145°-165°. 

 Tetragraptus-zone, Skane ; ? Phyllograptus-shales, Norway. 



25. Diclymograptus serratulus (Hall), ? Lapw. 



Hudson's River Group, New York ; ? Utica Slates, New York. 



26. Didymograptus striatulus, Linnarsson, Nich., Lapw. 

 Lower Graptolite shales, West Gothland. 



/. Type Diclymograptus V-fr actus, Salter. 



27. Diclymograptus V-fr actus, Salt., Nich., Lapw., Brogg., Tullb. 

 Skiddaw Slates, N. England ; Tetragraptus-zone, Skane ; Lower 



part of Phyllograptus-shales, Norway. 



28. Diclymograptus balticus, Tullb., Lapw. 



Resembles the preceding. — Angle of divergence 60°-105°. 

 Tetragraptus-zone, Skane ; Phyllograptus-shales, Norway. 



29. Diclymograptus Pantoni, M'Coy, Salt., Ether., Lapw. 

 Skiddaw Slates, N. England ; Australia. 



30. Diclymograptus vacillans, Tullb., Lapw., Brogger. 

 Tetragraptus-zone, Skane ; Phyllograptus-shales, Norway. 



31. Diclymograptus, sp. (Hisivgeri, Baily). Lower Bala, Ireland. 

 One of the latest species of Didymograptus. 



Genus II. Janogkaptus, Tullberg (Geol. For. Forh. vol. v. p. 314). 



From the usually indistinct sicula two branches issue in opposite 

 directions, or the whole hydrosoma is formed only of one branch. 

 The sicula is probably pressed into one branch. The angle of diver- 

 gence is very various. Hydrotheca? as in Didymograptus. 



The genus, which is somewhat problematical, is one of the latest 

 of the Dichograptidse. Its structure shows a remarkable agreement 

 with that of an irregularly developed Monograptid (M. lobiferus, 

 M'Coy), in which a second branch may sometimes be produced. 



1. Janograptus laxatus, Tullberg. 



Gymnograptus Linnarssoni-zone, Skane. A Janograptus is also 

 mentioned in other Glossograptus-zones. 



Other forms may be regarded as proceeding from a Didymograptus. 

 The two branches may divide dichotomously, producing a four- 

 branched form (Tetragraptus) ; or branchlets may issue from the two 



