Mr. Searles Wood estimates the total number of marine testaceous mollusca of the Coralline Crag at 350, of which 110 are not known as living, being in the proportion of thirty-one per cent extinct. No less than 130 species of bryozoa have been found in the Coralline Crag, and some belong to genera unknown in the living creation, and of a very peculiar structure; as, for example, that represented in Fig. 127, which is one of several species having a globular form. Among the testacea the genus _Astarte_ (see Fig. 128) is largely represented, no less than fourteen species being known, and many of these being rich in individuals. There is an absence of genera peculiar to hot climates, such as _Conus, Oliva, Fasciolaria, Crassatella_, and others. The absence also of large cowries (_Cyprea_), those found belonging exclusively to the section _Trivia_, is remarkable. The large volute, called _Voluta Lamberti_ (Fig. 123, p. 196), may seem an exception; but it differs in form from the volutes of the torrid zone, and, like the living _Voluta Magellanica_, must have been fitted for an extra-tropical climate. Fig. 129: Lingula Dumortieri. Fig. 130: Pyrula reticulata. Fig. 131: Temnechinus excavatus. The occurrence of a species of _Lingula_ at Sutton (see Fig. 129) is worthy of remark, as these _Brachiopoda_ seem now confined to more equatorial latitudes; and the same may be said still more decidedly of a species of _Pyrula_, supposed by Mr. Wood to be identical with _P. reticulata_ (Fig. 130), now living in the Indian Ocean. A genus also of echinoderms, called by Professor Forbes _Temnechinus_ (Fig. 131), occurs in the Red and Coralline Crag of Suffolk, and until lately was unknown in a living state, but it has been brought to light as an existing form by the deep-sea dredgings, both of the United States survey, off Florida, at a depth of from 180 to 480 feet, and more recently (1869), in the British seas, during the explorations of the “Porcupine.”