. Bulletin of the British Museum (Natural History), Geology. 200 SMITH species, P. cotteauanus (d'Orbigny) has a median zone of pores also. Thus, in many respects Pygurostoma is no more than an hypertrophic form of Parapygus in which the phyl- lodes have increased numbers of median pores and the periproct is inframarginal rather than marginal. Only one other species was included in this genus by Kier (1962), Pygurostoma pasionensis Cooke, 1949, from the late Cretaceous of Guatemala. However, this species has its periproct flush with the test and not invaginated. I suspect this is not coge
. Bulletin of the British Museum (Natural History), Geology. 200 SMITH species, P. cotteauanus (d'Orbigny) has a median zone of pores also. Thus, in many respects Pygurostoma is no more than an hypertrophic form of Parapygus in which the phyl- lodes have increased numbers of median pores and the periproct is inframarginal rather than marginal. Only one other species was included in this genus by Kier (1962), Pygurostoma pasionensis Cooke, 1949, from the late Cretaceous of Guatemala. However, this species has its periproct flush with the test and not invaginated. I suspect this is not cogeneric. Pygurostoma morgani Cotteau & Gauthier, 1895 PI. 23, figs 1-4, 7; Figs 60-63 1895 Pygurostoma morgani Cotteau & Gauthier: 52, pi. 8, figs 1-5. 1962 Pygurostoma morgani Cotteau & Gauthier; Kier: 135, pi. 19, figs 1-3, text-fig. 117. 1992 Pygurostoma morgani Cotteau & Gauthier; Ali: 72, fig. 4. Types. The whereabouts of Cotteau & Gauthier's specimens is unknown. A topotype specimen from the Morgan collec- tion is illustrated (PI. 23, fig. 1). Material studied. Forty specimens, of which 15 (BMNH EE3291-92, EE3296, EE3302-10, EE3315, EE3317, EE3322) were measured. Occurrence. The species was first described from the 'Upper Senonian1 of Aftab, Louristan, southern Iran. In this study specimens were most common in the lowest few metres 20 18 E, t: 14 12 â Peristome * Apical disc â â â ⦠⦠of the Simsima limestones. Fifty specimens were collected or noted at the following localities and horizons: Jebel Buhays, section 1: loose in the scree, derived from the lowest few metres of Simsima Formation (26). Jebel Buhays, section 2: loose in scree, derived from lowest 2 m of the Simsima Formation (2). Jebel Thanais: lowest 2 m of Simsima Formation (1). Jebel Huwayyah, section 1: beds 14/15 (3). Jebel Rawdah, section 2: bed 14 (3); bed 18 (1); bed 19 (2); bed 21 (7); bed 26 (2); loose in scree (1). Jebel Rawdah, section 4: bed 19 (1). Jebel Faiyah, section
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