Cal. Blumenbachi Salter Monogr. pl. 8, fig. 9. The identity of the species is dubious.
Cal. duplicata Salter Mon. pl. 9, fig. 22. The tubercles rather more linear and approximated than in the subsequent. Salter calls them »two small transverse lobes ... forming a nearly continuous ridge».
Cal. tuberculata Angel. Tab. XIX fig. 5 c from the inside.
It is remarkable that the eyes or that part of them where the cornea and the lenses should be found, has been destroyed and entirely lost in all specimens of the Calymmene known to us, many hundreds having been searched and every one with a lacuna on that spot. It must have been of an excessive thinness. We know only of one instance, the Bohemian Calym. Arago, in which Barrande has seen the eye intact and provided with a small number of about eleven sphærical lenses.
Calymmene intermedia Ldm.
The clypeiform hypostoma is divided in two fields, one anterior larger, in the centre elevated in a short, blunt knob, and a posterior, bearing the two elevated rounded maculæ, just below the semicircular groove which separates it from the anterior field. These fields are surrounded by a large border which is posteriorly emarginated through a short rounded sinus. The surface is entirely covered by small semiglobular wartlets perforated by a straight pore or duct, which being filled with a black mineral, probably iron pyrites, gives a peculiar and characteristic aspect to the sections. In the same manner the whole mass of the hypostoma is pierced by straight, black lines, also filled up pores, starting from the outside and ending before attaining the inner surface.
The maculæ are prominent, separated from the hypostoma through narrow, distinct grooves, ovate, with the pointed end directed obliquely outwards, against the margins of the hypostoma. They are covered with wartlets and leaving only a little oblong spot free, quite smooth, this being consequently the macula proper. But in a longitudinal section there is not the least distinction between this macula and the other hypostoma, only, that it is free of pores.
Calymmene tuberculata Brünnich.