J. Hopkinson — On Neiv British Graptolites, 503 



Order, Hydroida. Sub-order, Theoaphora ? Family, Dendroidea. 



1. Dendrograptus ramulus, sp. nov. — PI. XII., Fig. 2. 



Polypary with slender flexuous branches bifurcating at a wide 

 angle and bending outwards after each bifurcation, Hydrothecas 

 about 30 to the inch, nearly twice as long as broad, rhomboidal in 

 form, entirely free from each other, and with projecting sub- 

 mucronate apices. 



The branches usually occur in small fragments having a jointed 

 or articulate appearance, due to the complete separation of their 

 hydrotheciB from each other. They are about l-50th of an inch in 

 breadth. The hydrothecse usually have a slight inclination outwards, 

 or away from the dorsal margin of the branches, their proximal 

 angle projecting slightly on this side, and their extreme distal angle 

 or apex forming a rather more prominent projection on the frontal 

 or outer side ; but, owing to the varying direction of compression of 

 the branches, they sometimes assume very different forms. 



This species is very distinct from all the others of its genus. The wide angle of 

 divergence of its branches, and their decided aiticulate appearance, are its chief 

 characteristics. In form its thecae somewhat resemble those of B. gracilis (Hall), 

 but they are less triangular in shape, being very nearly, if not quite, as broad at their 

 proximal as at their distal end. 



More entire specimens of D. ramulus than have hitherto been found would be of 

 value. 



Loc. Llandeilo : — "Wanlock "Water, "Wanlockhead, Lanarkshire. 



Order, Hydroida. Sub-order, Ehabdophora. Family, Monoprionid^. 



1. GraptoUthus atteniiatus, Hopk. (Expl. Sh. 15, Geol. Surv. 

 Scotl.)— PI. XII., Fig. 3. 



Polypary exceedingly slender, slightly curved, and with isolated, 

 linear, or linear-tubular hydrothecaB, from 10 to 12 to the inch, 

 rising from its convex margin at a very slight angle. 



This little, fragile, monoprionidian graptolite seems to have been 

 about an inch or two in length, none of the specimens examined 

 exceeding an inch an'd a half, and this length is but rarely attained. 

 The curvature of the polypary, though very slight, is constant in 

 different individuals. Tiie periderm is about l-400th of an inch in 

 breadth, and is thus of greater tenuity than in any other species of 

 the genus. The proximal end of the hydrothecee is not clearly 

 defined, for they merge imperceptibly into the periderm at their 

 origin. There appears, however, to be a slight interval between the 

 distal end of each theca and the proximal end of the next. From 

 their origin the hydrothecse gradually widen to a maximum breadth 

 of l-150th of an inch, terminating in a rounded apex, which shows, 

 when a front view of the polypary is obtained, a distinct circular 

 aperture ; but when the polypary is compressed so as to show a side 

 view, these apertures are not visible, the apex of the thecal being 

 slightly pointed and free from the adjoining portion of the polypary. 



This species seems to be more nearly allied to Rastriies capillaris (Carr.) than to 

 any species of Graptolitlms. It differs, however, from the typical species of Eastrites 

 in its hydrothecse being closely appressed to the periderm from their proximal to their 

 distal end. It apparently forms, with R. ca'pillaris, an intermediate link between the 

 two genera, if they are really distinct. 



The most nearly allied form in GrcqitoUthus is Prof. Nicholson's var. minor of G. 

 Nilssoni (Barr.), but in this variety there are nearly twice the number of hydrotheca; 



