202 Dr. Ivor Thomas — Trilohite Fauna of Devon and Cormoall. 



and rounded anterior margin. Two well-marked basal lobes are present, 

 and minute tubercles adorn the surface especially near the base. 

 A pre-ocular pore is seen on the left margin near the frontal border. 

 The well-developed marginal border of the head-shield is ornamented 

 with narrow, curved furrows approximating in direction to that of the 

 outer margin, while the genal extremity is produced into a prominent, 

 slightly curved spine. The eyes are not preserved. 



A portion of the thorax is present, and shows four rings of the 

 rounded and elevated axis, which is bounded by well-marked furrows 

 and is approximately equal in width to the lateral pleural area. The 

 broad pleura are grooved down the centre and curve slightly backwards. 

 JN^umerous minute tubercles ornament the whole surface. 



The pygidium is 4 mm. long and about 5 mm. broad, and has a 

 convex, very gradually tapering axis with about thirteen segments. 

 The lateral pleural area is tumid and possesses at least eight segments, 

 which curve very slightly backwards. Indications of a faint marginal 

 bifurcation are present in some of the rings. Both axis and pleural 

 areas are adorned with minute tubercles. The fairly broad marginal 

 border narrows slightly anteriorly, and is apparently without distinct 

 ornamentation. Its extreme posterior extremity is somewhat angular. 



Localiti/ and Horizon. — The same as the preceding. 



RemarTcs. — The preservation of the head-shield is imperfect, but 

 judging from the parts of that region in good condition it could well 

 be assigned to PhilUpsia minor. Examination of the pygidium, which 

 by its proximity and position in the hand-specimen undoubtedly belongs 

 to the head, shows, however, that this determination would be doubtful. 

 The pygidial axis of Ph. tninor is considerably more tapering, while 

 the marginal border of the same species is much more curved than, in 

 our form. 



Phillipsia sp. PI. YII, Pig. 14. 



Description. — A fairly well-preserved cast of a head fragment 

 shows an elongated tumid glabella with sub-parallel lateral borders 

 and a very rounded anterior extremity. The length of the glabella 

 is 5"5mm., and its greatest breadth 3 mm. The triangular basal 

 lobes are well marked and bounded by a strong pair of lateral 

 furrows. A second pair of furrows occur anteriorly to the latter. 

 These are directed inwards and backwards, and gradually become 

 shallower as they approach one another posteriorly. In this manner 

 a second pair of elongated lobes are marked off and a V-shaped 

 sculpture given to the glabella. Anteriorly to the second pair of 

 furrows, and about half-way between them and the frontal extremity, 

 is a small marginal pitting on either side corresponding to the pre- 

 ocular pores. The frontal lobe is separated from the raised anterior 

 termination of the head-shield by a shallow depression. The facial 

 sutures cut the curved frontal border of the shield at a distance of 

 about 6 "5 mm. apart. They run at first slightly outwards, then turn 

 backwards and inwards, and are again deflected slightly outwards 

 at a short distance from the second pair of glabella lobes. Prom 

 this point they curve inwards and backwards near the basal lobe, 

 finally running in a shallow curve outwards and backwards, and 



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