482 MISS G. L. ELLES ON THE GEAPTOLITE [Aug. 1 898, 



characters of the thecse clearly ; the remaining stipes show the thecal 

 apertures, or else the dorsal side of the stipe is turned towards 

 the observer, and nothing is seen of the thecae. The stipes are 

 narrow at their origin, but widen to a maximum width of -^ inch 

 (2-1 mm.). 



The thecEe are of the general Dichograptus-type ; they number 

 twenty-four to the inch (nine to ten in 10 mm.), are inclined at 

 55°, and are in contact for the greater part of their length. The 

 apertures are submucronate, and are inclined to the general direction 

 of the stipe at an angle of 130°. 



The specimen is in Mr. Postlethwaite's collection. 



Localities. — Carlside Edge; Scale Hill, near Crummock (type- 

 specimen). 



Genus Pteroyraptus, Holm. 



Pterogeapttjs (?) sp. 



At Aik Beck there occur numerous broken stipes of a graptolite 

 which seems more closely related to Pterograptus, Holm, than to 

 any other known form. All the specimens that I have seen belong 

 to Prof. H. A. Nicholson, by whom they were sent to me. 



The stipes so often appear isolated that I am inclined to think 

 that their attachment to the main stipe must have 

 been of a very slender nature ; this fact led me Fig. 9. 



at first to think that the form was a new species Pterograptus (?) : 

 belonging to the genus Azygograptus, until I coll. Nicholson.' 

 developed out a specimen showing lateral stipes 

 still attached to the main stipe. f 



The branching in this specimen and the general 

 characters of the rhabdosoma (so far as I have been 

 able to make them out) recall some Swedish 

 specimens of Pterograptus, which differ from the 

 species described by Holm. In view of the frag- 

 mentary condition in which the form occurs in 

 the Skiddaw Slates I will not attempt a specific 

 diagnosis, but will merely note the characters so [Nat. size.] 



far as I have been able to determine them. 



All the stipes are alike, and gradually widen from their point of 

 origin to a maximum width of -^-^ inch (about "5 mm.) opposite the 

 apertures of the thecse. 



The branching appears to take place at fairly regular intervals 

 along the main stipe, but is different from that of Pterograptus 

 elegans, Holm. In that species branches are given off from each 

 of the first seven thecse on each main stipe, but in the form in the 

 Skiddaw Slates there are at least three thecae between the lateral 

 stipes. The lateral stipes are given off alternately on each side of 

 the main stipe. All the stipes are concavely curved, and the 

 thecse are always on the inside of the curve. These number between 

 fifteen and twenty to the inch (seven to eight in 10 mm.) : they 



