10 



BRITISH FOSSILS. 



2. Phacops Brongniarti, Portlock (1843), Geol. Rep. Tyrone, pi. 2. fig. 8. (excl. ref.) P. 

 Murchisonii, ib. fig. 9. 



P. biuncialis, elongatus granulatus, modice convexus ; capite longo trigono, fronte angulato 

 subrecurvo ; glabella ad basin contractd anterius valde dilatatd nec convexd, lobis iitrinque 

 tribus radiantibiis ; lobo antico maximo triangulato, a frontali sulco valido — a medio sulco 

 leviore — sejuncto ; lobis infimis minutis hemisphcericis circumscriptis sese remotis ; lobo verti- 

 cali eminentiore ; oculis maximis, a lobo froniali usque ad sulcum verticalem tractis ; angulis 

 genarum obtusis; thorace axi convexo angustato, lateribus parallelis abrupte deflexis ; 

 pleurarum apicibus rotundatis, fulcro intra medium posito ; caudd trigond, axi longe conico 

 angustissimo fere ad finem caudce extenso, decies annulato ; apice prominulo ; lateribus 

 5-costatis, costis per totum divisis, nec marginem Icevem attingentibus. 



Col. Portlock had united with this species both the P. macrophthahia of Brongniart, 

 and P. Downingice, Murch. They are however, as above stated, quite distinct 

 species. The present is well characterized by the pointed front and contracted base 

 of the glabella, as well as by the large eyes, which have each 170 lenses. 

 Localities. — Bala and Llandeilo Rocks : Tyrone ; Carrickadaggan, Wexford ; Llan- 

 fyllin, and other places, N. Wales. 



3. P. Dalmanni, Portl. 1. c. f. 7. 



Omnino precedenti simillimus — caudd multi-annulatd, oculis maximis, glabelld ad basin 

 contractd, granulosd; sed capitis fronte rotundato, nec producto ; [aw forsitan fcemina 

 inermis?'] 



This neat species occurring with the last, and of the same or of rather less dimensions, 

 so much resembles it in form, proportion, and sculpture, that we are compelled to 

 regard it as of the same species, and as indicating either a variety with a rounded 

 front, or, what is more likely, the female form. Portlock's original specimens 

 are all of one character, and the front appears to have been really rounded, not 

 broken off. 



Locality. — ^Desertcreat, Tyrone. 



4. P. Jamesii, Portlock, G. Report, pi. 3. fig. 10. (mala). 



P. unciani latus ; capite semicirculari, bis quam longo latiori, fronte angulato, marginato, 

 crasso; glabelld ferepland tuberculatd antice latissimd postice ad dimidium contractd, lateribus 

 rectis ; lobo frontali late triangulato, oculis impendente ; cceteris radiantibiis, — supremo maximo 

 triangulato, medio lineari obliquo haud abbreviate, basali transverso ; lobis omnibus fere ad 

 medium glabella, spatio angusto interjecto, conniventibus ; genis lente declivibus marginatis, 

 angulis obtusis ; oculis abbreviatis valde curvatis ; (thorace — ?) caudd [und cum capite 

 congregata'] rotundatd, quam longd tertiam partem latiori, depressd ; axi satis magna conico, 

 marginem nullo modo attingente, — annulis 8-9 ; lateribus sulcis 6-7 cequalibus, laviter inter- 

 lineatis. 



Portlock's figure but imperfectly expresses the great width and flatness of the glabella, 

 which is not the result of pressure ; the tuberculation covers the glabella only, while 

 the cheeks are merely granulated. The shape of the glabella and its radiating 

 lobes, and the short curved eye, approximate this species nearly to the next, from 

 which the glabella and pointed front of the head readily distinguish it. The head 

 too is not so broad in proportion. 



Locality. — Tyrone ; in calcareous sandy schist, Waterford ; also in sandstone at New- 

 town on the Suire, in the same county. [Geol. Surv, Coll.] 



5. P. alifrons, Salter, in Appendix to Sedgwick's Brit. Pal. Foss. l.c. ii. t. 1 G. f. 12-14, 

 M'Coy, ib. 159. 



P. capite sesqui-unciam lato, gibboso, tuberculoso, antice truncato, bis quam longo latiori; 

 glabelld elevatd sed paullum convexd, ad basin angustatd, superne dilatatd obtusd, lateribus 

 subrectis; lobo frontali brevi transverso limbum crassum impendente, et utrdque angulis 



