. Bulletin of the British Museum (Natural History). Fig. 18 Calymenella sp. A. Specimen from Loc. A. a, b, c: Itl9814 (x2), latex cast of external mould of cranidium. Description. Dimensions of the single cranidium known: 22 mm long (sag.), 34 mm wide (tr.) and 13 mm high. Outline of cranidium well rounded, semicircular to slightly triangular. Glabella outline similar to that of cranidium, highly domed; it occupies half the total height of the cranidium. Maximum elevation is just anterior to occipital furrow and in profile curves down smoothly to anterior. Glabella featureless except
. Bulletin of the British Museum (Natural History). Fig. 18 Calymenella sp. A. Specimen from Loc. A. a, b, c: Itl9814 (x2), latex cast of external mould of cranidium. Description. Dimensions of the single cranidium known: 22 mm long (sag.), 34 mm wide (tr.) and 13 mm high. Outline of cranidium well rounded, semicircular to slightly triangular. Glabella outline similar to that of cranidium, highly domed; it occupies half the total height of the cranidium. Maximum elevation is just anterior to occipital furrow and in profile curves down smoothly to anterior. Glabella featureless except for occipital furrow and faint IP furrow that forms an approximately straight depression from axial posterior of glabella to palpebral lobe, and separates off the somewhat inflated IP lobe. Occipital ring widens axially and is poorly developed behind IP lobes. Preglabellar field 0-29 of total cranidial length (sag.) and approximately half preoccipital length (sag.) of glabella. Neither preglabellar nor axial furrows clearly developed, the margins of the glabella marked by sharp changes of slope. Posterior two-thirds of preglabellar field slopes gently down- wards whilst anterior third is sharply curved down. The gently sloping area appears to narrow slightly as it curves towards the palpebral lobes, whilst the steeply sloping portion remains approximately the same width when viewed dorsally. Palpebral lobe only slightly separated from glabella and in profile is approximately level with the base of glabella. It lies just over half way along the sagittal line of the cranidium, at between 0-49 and 0-59, and is only slightly elevated above the fixed cheeks. Posterior to palpebral lobe is a gently sloping area of the fixed cheek, widening posteriorly. Posterior border furrow only faintly developed though posterior border is quite strongly inflated and widens quite significantly abaxially. In lateral view the facial sutures indicate a relatively small free cheek, the preocular
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