CLIMACOGRAPTUS. 



205 



Fia. 135 o- 



— Climacograptus UUi 

 sp. nov. 





i. Proximal end, obverse view. Dobb's 

 Linn, Upper Hartfell Shales (zone 

 of Dicellog. anceps). Coll. Elles. 



i. Reverse view showing basal spines 

 well. Ibid. Coll. Wood. 



;. Reverse view showing a somewhat 

 different appearance of the proximal 

 end. Enlargement of part, of PL 

 XXVII, fig. .3 ./. 



Fig. 135 (J. — Climacograptus lain*, sp. 

 nov. 





</. Distal thecee, showing great width of 

 distal part of polypary. Enlarge- 

 ment of pari of PL XXVII, fig. 3 d. 



Description. — The rapid increase in width in the 

 earlier and the more gradual increase in the later 

 stages of growth are extremely characteristic of 

 this species. The average length of the distal 

 thecae is 2 mm., but the proximal theca? are much 

 shorter and grow more horizontally than is com- 

 monly the case in the Glimacograpti, and the lateral 

 excavations are deeper. 



Affinities. — CI. latns may be distinguished from 

 all other Glimacograpti by (1) the relatively great 

 width of the polypary compared with the relative 

 shortness of the theens at the proximal end, (2) the 

 rapid increase in width for the first few millimetres 

 of growth, and (3) the more gradual increase at a 

 later stage. 



Horizon, and Locality. — Upper Hartfell Shales 

 (zone of Dicellog. anceps). 



S. Scotland.— Dobb's Linn. 



Associates, etc. — CI. latns occurs with D. anceps 

 at the top of the Hartfell Shales ; it is not a 

 common fossil. 



Collection. — The Authors. 



Climacograptus styloideus, Lapworth MS. Plate XXVII, figs. 



1878. 



Climacograptus styloideus, Lapworth, Quart. Journ. GTeot. Soc, vol. xxxiv, p. 330. 



Polypary long and narrow, from 4 to 7 cm. in length, and with a breadth of 



2 — 2-5 mm., which is attained early, so that the margins are subparallel 



for the greater part of their length. Sicula 3 mm. in length, virgella short, 



virgula long. Thecse, overlapping for very small fraction of their extent, 



twelve to eight- in 10 mm., I '5 mm. in length. Apertnral margin oblique, 



situated in narrow elliptical excavations occupying one-fourth to one-third 



of the width of the polypary. 



Description. — The polypary varies much in length (but the longer specimens 



are the more characteristic); it has the appearance of being bluntly pointed at 



the proximal end. The virgella is lmt rarely preserved, and although the two 



27 



