4 



BRITISH FOSSILS. 



shown more clearly the upper pair of glabella furrows and the 

 outwardly placed head spines ; the eye is also too small. 



Locality and Geological Position. — Upper Lingula Flags? 

 Carreg Wen, Borth, Portmadoc. (Mus. Pract. Geology.) 



OLENUS (PARABOLINA) SERRATUS. 



Plate VIII. Fig. 5. 



Diagnosis. 0. modicus, \^-uncialis, convexus. Glabella oblonga 

 cequilata, haud parabolic a, antice subfruncata, sulcis utrinque bijiis longis 

 fere medium glabellce attingentibus., pattllo obliquis. Sulcus cervicalis vix 

 continuus. Oculi valde antici. Geuce angustce. Cauda {Jdc hand dubie 

 refertci) semicircularis axi pronmiulo 4 costato, obtuso ; lateribus utrinque 

 S-dentatis, dentibus patulis limbo brcvioribus ; hoc 4-sulcato, sulcis 

 omnibus distincte interlineatis. 



Synonyms. Olenus {Parabol.) serratus, Salter, Mem. Gaol. Surv., 

 vol. iii. ined. pi. 5, figs. 6, 7- 



Descripiion. — Glabella quite as wide in front as behind, with a 

 broad neck segment, equal in breadtli to the basal lobe. The second or 

 middle lobe somewhat na^rrower. Fixed cheeks broad, sub-trigonal, 

 equal to more than half the width of the glabella, the eye placed 

 very far forwards, opposite the forehead lobe. Free cheeks not 

 known, probably narrow. 



Tail, most likely of the same species, semicircular, serrate, with 

 short, somewhat radiating spines. Axis thick, of four prominent rings 

 and a blunt terminal piece ; sides four-ribbed, the ribs duplicate, 

 and produced on the margin into strong spines of less length than 

 the limb, five on each side, the fifth pair of spines being set rather 

 wide apart beneath the axis. 



Affinities. — I much wish I could identify this with the common 

 0. spinulosus, Wahl, for the head is very like. But the caudal 

 shield is decidedly different, and as it in all probability belongs to 

 the same species as the head, I feel bound to keep the two distinct. 

 The glabella, moreover, differs, as above described, from that of the 

 true 0. spinulosus, which tapers a little forward. In that species 

 the tail spines also are greatly lengthened. 



History. — The section Paraholina, regarded as a genus by 

 Angelin, was proposed by me in 1849 to distinguish the species of 

 Olenus which have 12 body rings and a laciniate tail. 0. scara- 

 hceoicles might perhaps belong to this sub -genus as so defined, but 



