CLIMACOGRAPTUS. L85 



widening from the proximal end, so that the margins are sub-parallel for the 

 greater part of their extent. 



The short, robust virgella is always conspicuous, and usually measures about 

 1 mm. in length. The sicula is almost entirely concealed by the growth of th. I 1 

 and th. I' 2 , so that the proximal end presents a symmetrically rounded off 

 appearance, especially on the reverse aspect. 



The septum appears to originate at once, and to be complete from the earliest 

 stages. 



The virgula is often prolonged beyond the distal end of the polypary. 



Remarks. — The foregoing description has been drawn up from British 

 specimens which agree very closely with specimens from Hisinger's typical 

 locality. Hisinger's species has been recorded from many localities, but these 

 identifications appear to be erroneous; the form is a rare one in Britain, and 

 has never hitherto been figured from any locality in the British Isles; all the 

 figured forms hitherto referred to Gl. scalaris belong to one or other of the varieties 

 or species described below. 



Affinities. — The characteristic features of Gl. scalaris (His.), are the following : 



(1) Its complete septum ; 



(2) Its symmetrical proximal end, with a short virgella; 



(3) Its small size. 



Distal fragments resemble those of Gl. rectangularis and Gl. medius, but when 

 the complete polypary is seen there are marked differences in the proximal ends. 

 From Gl. recta lujitlaris, Gl. scalaris differs in its lesser width and smaller size, 

 while from Gl. medius it may be distinguished by its smaller size, shorter virgella, 

 and more complete septum. 



Horizon and Localities. — Upper Birkhill Shales, Lower Gala Beds and their 

 equivalents. 



8. Scotland: Dobb's Linn; Belcraig Burn; Lockerbie, etc. Ireland: 

 Donaghadee; Pomeroy. Wales : Conway; Llanystwmdwy ; R. Twymyn, etc. 

 Lake District : Skelgill, etc. 



Associates, etc. — Gl. scalaris is a rare fossil in the British Isles, though it 

 appears to be present in small numbers wherever the Upper Birkhill Shales or 

 their equivalents are found. It seems to occur most commonly at the base of the 

 zone of Monog. Sedgwichi and to be associated with Monog. lobiferus and 

 Gephalog. petalum. It is also met with more rarely in the Lower Gala, Beds 

 associated with Rastrites maximu-s and Monog. turriculatus. 



Collections. — Sedgwick Museum, the Authors, etc. 



