=Fossil Garpikes.=—A number of fossil garpikes, referred by Cope to the genus _Clastes_ and by Eastman and Woodward to _Lepidosteus_, are found in the Eocene of Europe and America. The most perfect of these remains is called _Lepisosteus atrox_, upward of four feet long, as large as an alligator-gar, which the species much resembles. Although found in the Eocene, Dr. C. R. Eastman declares that "it has no positively archaic features. If we inquire into the more remote or pre-Eocene history of Lepidosteids, palæontology gives no answer. They blossom forth suddenly and fully differentiated at the dawn of the Tertiary, without the least clue to their ancestry, unheralded and unaccompanied by any intermediate forms, and they have remained essentially unchanged ever since." Another fossil species is _Lepisosteus fimbriatus_, from the Upper Eocene of England. Scales and other fragments of garpikes are found in Germany, Belgium, and France, in Eocene and Miocene rocks. On some of these the nominal genera _Naisia_, _Trichiurides_, and _Pneumatosteus_ are founded. _Clastes_, regarded by Eastman as fully identical with _Lepisosteus_, is said to have the "mandibular ramus without or with a reduced fissure of the dental foramen, and without the groove continuous with it in _Lepisosteus_. One series of large teeth, with small ones external to them on the dentary bone." Most of the fossil forms belong to _Clastes_, but the genus shows no difference of importance which will distinguish it from the ordinary garpike. [Illustration: FIG. 24.—Lower jaw of _Amia calva_ Linnæus, showing the gular plate. ] =Order Halecomorphi.=—To this order belong the allies, living or extinct, of the bowfin (_Amia_), having for the most part cycloid scales and vertebræ approaching those of ordinary fishes. The resemblance to the _Isospondyli_, or herring group, is indicated in the name (Halec, a herring; μορφή, form). The notochord is persistent, the vertebræ variously ossified. The opercles are always complete. The branchiostegals are broad and there is always a gular plate. The teeth are pointed, usually strong. There is no infraclavicle. Fulcra are present or absent. The supports of the dorsal and anal are equal in number to the rays. Tail heterocercal. Scales thin, mostly cycloid, but bony at base, not jointed with each other. Mandible complex, with well-developed splenial rising into a coronoid process, which is completed by a distinct coronoid bone. Pectoral fin with more than five actinosts; scales ganoid or cycloid. In the living forms the air-bladder is connected with the œsophagus through life; optic chiasma present; intestine with a spiral valve. This group corresponds to the _Amioidei_ of Lütken and essentially to the _Cycloganoidei_ of Gill. The _Protospondyli_ (προτός, before; σπόνδυλος, vertebra) of Woodward contains essentially the same elements.