NEMAGRAPTUS. 



131 



Pig. 78.- 



-Nemagraptus gracili 

 remotus, nov. 



V 



4/ 



Proximal end. Enlargement 

 PI. XIV, fig. 3 d. 



part of 



The sicula is about 1 mm. in length. 

 The thecse number ten in 10 mm., they are 

 inclined at 10°, have an average length of 1*5 mm., 

 are five times as long as wide, and are in contact 

 for only a small fraction of their extent. 



Affinities. — This species is closely allied to 

 N. gracilis in general form, but differs in the position and number of the secondary 

 branches and their greater tenuity; there are also more thecse in a given unit of 

 length. From all other Nemagrapti it may be distinguished by the direction of 

 growth of the main stipes. 



Horizon and Localities. — Upper Llandeilo (Grlenkiln). 



8. Scotland : Belcraig Burn; Grlenkiln Burn; Rein Gill; Morrach Bay. 

 Ireland : Ballygrot. 



Associates, etc. — Var. remotus occurs in the Glenkiln Shales of S. Scotland, 

 associated with Didymog. superstes, Dicellog. sextans, Nemag. gracilis, etc. It is not 

 a common form. The best specimens known are in the collections of the Geo- 

 logical Survey of Scotland, and the private collections of Lap worth and the 

 Authors. 



Var. nitidulus (Lap worth). Plate XIX, figs. 4a — d. 



1&76. Coenoyraptus nitidulus, Lapwortli, Cat. West. Scott. Foss., pi. iii, fig. 66. 



Description. — A third variety is that to which Lapwortli has given the name 

 nit id a I ns. This is characterised by the tenuity of the stipes, which average '3 mm. 

 in breadth, and the fact that the branches, which are few in number, are usually 

 on the inner side of the curve. The main stipes have a length of about 2 cm. 

 They diverge from a conspicuous sicula at an angle of about 180°, hut after 

 giving origin to two thecae curve upward so as to include a much smaller angle. 

 They have a typical sigmoidal curvature, but being very flexed and slender this 

 curvature is often extreme and irregular, and the stipes are bent back on them- 

 selves. There is generally evidence of one secondary branch on each main 



stipe, arising close to the sicula. These have a 

 length of 7'5 mm. and a breadth of about ••"! mm., 

 though they are not perfectly uniform in width, 

 undergoing a slight and almost imperceptible 

 increase along their extent. 



The sicula is conspicuous; it has a length of 

 1*3 mm. The first theca originates about midway 

 between its apex and aperture, and grows down- 

 ward and then outward ; the initial portion of th. 1 J 



and b. — Ncmagraptus gracilis, 

 var. nitidulus (Lapw). 



a. Obverse view. 



b. Reverse view. Both specimens on 



same slab. Enlargement of part of 

 PI. XIX, fig. Ifc. 



