|_S. vulgare_, | |39 | | |19 | | | |10 | | | | |10-11 | | | | | |5-6 | | | | | | |6 | | | | | | | |7 |_S. ornatum_, | |36 | | |21 | | | |10 | | | | |12 | | | | | |-- | | | | | | |-- | | | | | | | |-- |_S. Peronii_, | |30 | | |19 | | | |-- | | | | |9 | | | | | |6 | | | | | | |5 | | | | | | | |10 POLLICIPES: disc small, _hoof-like_, not pointed, with a single spine on the hinder margin; end segment, as in _Scalpellum_. |_P. cornucopia_, | |20 | | |-- | | | |6 | | | | |6 | | | | | |6 | | | | | | |6 | | | | | | | |8 [61] In the diameter of the disc, the thin membranous border, which is present in the first three genera, is included; but I have some doubts, whether this border be not the first rim of cementing tissue, as all the specimens, of which measurements are here given, had been removed after attachment. In using the terms inner and outer sides of the end segment, it is supposed, that this segment is stretched straight forwards, instead of being bent rectangularly outwards, as in its natural position; and then there can be no doubt which is the inner and outer sides.