Mr. C. Lapworth on new British Graptolites. 159 



Cyrtograptus Linnarssoni differs from C. Murchisoni, Carr., 

 in the greater tenuity of the branches, in their much rarer 

 subdivision, and most especially in the form and proportions 

 of the adult hydrothecae. Baily's figure of his Didymo- 

 graptus (Cyrtograptus) hamatus reminds us of the young of 

 the present species ; but in his form there are at least eight 

 proximal hydrothecae, while the distal hydrothecae are of the 

 type of those of M. Nilssoni, Barr., and more like those of 

 Cyrtograptus Carrutkersi, Lapw. 



I name this well-marked species after Mr. G. Linnarsson, 

 the eminent palaeontologist to the Swedish survey, to whom 

 all palaeontologists owe a debt of gratitude for his minute and 

 accurate memoirs on Swedish palaeontology. 



Horizon and Locality. Cyrtograptus Linnarssoni is met 

 with in some abundance in the Wenlock shales of the neigh- 

 bourhood of Builth, Radnorshire. I have collected a few 

 fragments in the Wenlock shales of Presteign and the vale 

 of the Onny, above Horderly, Shropshire. 



Family Leptograptidae. 



14. Azygoqraptus ccelebs, sp. nov. 

 (PI. V. figs. 16a-16c.) 



Polypary unilateral, monoprionidian, consisting of a single, 

 simple and very . slender, slightly recurved stem a few inches 

 in length, proceeding from the major extremity of a well- 

 marked sicula. Hydrothecae twenty-five to the inch, in 

 contact only, expanding slightly in the direction of the 

 aperture, which is acute, straight, and facing slightly in- 

 wards ; outer margin slightly convex ; denticle blunt, a little 

 everted. 



This species is known to me only in the form of a few frag- 

 ments from the Upper Skiddaw slates of Ellergill, Cumber- 

 land, where it was collected by myself in 1874. One example 

 only shows the sicular extremity ; but this is beautifully pre- 

 served and exhibits the generic and specific characteristics of 

 the form most distinctly. The longest fragment is about 

 two inches in length. In the sicular fragment the hydro- 

 thecae, which are preserved as casts, distinctly overlap each 

 other for a very short distance. In the compressed examples 

 they appear to be wholly free, and have the general character- 

 istics of those of Leptograptus and its allies. They expand 

 more rapidly in the direction of the aperture than in Lepto- 

 graptus ; but this is a feature which Azygograptus shares 

 with Cosnograptus and, indeed, all the earlier forms of the 

 Leptograptidae. There is some evidence of the usual faint 



