. Bulletin of the British Museum (Natural History), Geology. Fig. 62 Camera lucida drawing of apical disc plating in Pygurostoma morgani Cotteau & Gauthier, BMNH EE3288. Scale bar = 1 Fig. 63 Camera lucida drawing of phyllode plating in Pygurostoma morgani Cotteau & Gauthier, BMNH EE3304. Scale bar = 5 Occurrence. This species occurs abundantly at Jebel Raw- dan, section 2 but is found virtually nowhere else. The only other occurrence of this species is in the lowest bed (bed 1) at Jebel Rawdah, section 3b. At section 2 the species is found at the following levels: bed 4 (3); bed
. Bulletin of the British Museum (Natural History), Geology. Fig. 62 Camera lucida drawing of apical disc plating in Pygurostoma morgani Cotteau & Gauthier, BMNH EE3288. Scale bar = 1 Fig. 63 Camera lucida drawing of phyllode plating in Pygurostoma morgani Cotteau & Gauthier, BMNH EE3304. Scale bar = 5 Occurrence. This species occurs abundantly at Jebel Raw- dan, section 2 but is found virtually nowhere else. The only other occurrence of this species is in the lowest bed (bed 1) at Jebel Rawdah, section 3b. At section 2 the species is found at the following levels: bed 4 (3); bed 8 (4); bed 11 (247); bed 12/13 (230); bed 14 (17); bed 15 (25); bed 19 (73); beds 20-21 }(45); bed 22 (13); bed 26 (2). Additional material was collected loose from the scree at this locality. 'Diagnosis. A Petalobrissus with a monobasal apical disc and a small quinquestellate peristome, anterior in position and surrounded by small pointed bourrelets. Phyllodes well- developed, composed of outer and inner series of pores. Buccal pores present. Periproct posterior, longitudinal. Nar- row, smooth tubercle-free zone present both anterior and posterior to the peristome. In outline the posterior projects slightly and adorally there is a characteristic interradial keel in the posterior interambulacrum. Description. Tests are oval in outline, uniformly rounded at the anterior, but slightly pointed posteriorly (PI. 24, figs 5, 6). Test length ranges from 10-3 to 21-2 mm. Test width is 88-95% of test length (mean = 91%, SD = 1-8%, N = 23) and the widest point is slightly posterior of midlength. In profile the test is depressed with a relatively flat upper surface, a uniformly rounded anterior and an obliquely truncated posterior (PI. 24, figs 4, 7, 10, 11). The tallest point coincides with the apical disc or is slightly posterior to it. The ambitus is rounded and relatively low. Test height is 51-62% of test length (mean = 56%, SD = 2-4%, N = 23; Fig. 64). The oral surface is flat anter
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