12 GEOLOGICAL MEMOIRS.
extensive family, beginning with Trachyceras and comprehending the
genera Cosmoceras, Toxoceras, Crioceras, the Flexuosi, and a good
number of Scaphites.
On Living and Fossil Algae. By Dr. A. Boue.
[Proc. Imp. Geol. Inst. Vienna, January 18, 1870.]
The living Algoe consist of a stem, more or less thick, and often of considerable thickness in large species, and of a foliage very diversified in quantity, length, and thickness. The movement of the waves, or any other external action, may compress or distort the wing-like leaves of certain Algoe, and thus give rise to indistinct, partly torn, or extended forms, such as are occasionally met with in Eocene Carpathian Sandstones. The round and oval forms conspicuous on some specimens may be somewhat flattened, and thus apparently enlarged, fructifications, as they appear occasionally nearly isolated on some stems, the foliage having been nearly destroyed. Possibly the fragments and impressions not rarely occurring in fucoid shales and Eocene sandstones, and generally ascribed to Monocotyledones, may be fragments of species of the genus Zostera, one species of which is constantly associated with Algae in the northern seas. Their very large and rather slender portions float in the water like those of the Euei ; they are easily torn and divided, and have some analogy in structure with the lengthened and undetermined fragments in fucoid deposits. Zosterites is known to occur in Eocene deposits, and such marine plants may more probably be found associated with Algae than any land plants. If the above-mentioned impressions were really those of Monocotyledons, those of many other terrestrial genera might be expected to be found associated with them.
On COELACANTHus. By Dr. von Willemoos-Suhm.
[Proc. Imp. Geol. Inst. Vienna, December 18, 1869.]
Dr. von Willemoos-Suhm has published (Palaeontographica, xvii. 1869) a monograph of Coelacanthus and some genera closely allied to it. The species described are C. macrocephalus, sp. n., C. Hassioe, Munst., C. (Undina) minutus, Wagner, C. penicillatus, Munst., and C. major, Wagner, all from the copper-shales and from the shales of Solenhofen and Cirin. There is no generic difference between the species from the copper-shales and those (Undina) from the Lithographic shales, closer examination having proved these latter (C. macrocephalus and C. Hassioe) to possess the characteristic deep fissure of the pectoral fin, the ossified swimming-bladder, and the articulation of the unpaired fins on bifurcated plates. The author unites with Coelacanthus the genus Graphiurus, Kner, from the Raibl shales, and refutes the generic claims of Macropoma, Agassiz.
