=The Mojarras: Gerridæ.=—The _Gerridæ_, or _Mojarras_, have the mouth equally protractile, but the form of the body is different, being broad, compressed, and covered with large silvery scales. In some species the dorsal spines and the third anal spine are very strong, and in some the second interhæmal is quill-shaped, including the end of the air-bladder, as in _Calamus_. Most of the species, including all the peculiar ones, are American. The smallest, _Eucinostomus_, have the quill-shaped interhæmal and the dorsal and anal spines are very weak. The commonest species is the silver jenny, or mojarra de Ley, _Eucinostomus gula_, which ranges from Cape Cod to Rio Janeiro, in the surf along sandy shores. Equally common is _Eucinostomus californiensis_ of the Pacific Coast of Mexico, while _Eucinostomus harengulus_ of the West Indies is also very abundant. _Ulæma lefroyi_ has but two anal spines and the interhæmal very small. It is common through the West Indies. _Xystæma_, with the interhæmal spear-shaped and normally formed, is found in Asia and Polynesia more abundantly than in America, although one species, _Xystæma cinereum_, the broad shad, or Mojarra blanca, is common on both shores of tropical America. _Xystæma gigas_ is found in Polynesia, _X. oyena_ in Japan, and _X. filamentosum_ in Formosa and India. _Xystæma massalongoi_ is also fossil in the Miocene of Austria. The species of _Gerres_ have very strong dorsal and anal spines and the back much elevated. _Gerres plumieri_, the striped mojarra, _Gerres brasiliensis_, the patao, _Gerres olisthostomus_, the Irish pampano, and _Gerres rhombeus_ are some of the numerous species found on the Florida coast and in the West Indies. The family of _Leiognathidæ_, already noticed (page 287), should stand next to the _Gerridæ_. [Illustration: FIG. 287.—Irish Pampano, _Gerres olisthostomus_ Goode & Bean. Indian River, Fla. ] =The Rudder-fishes: Kyphosidæ.=—The _Kyphosidæ_, called rudder-fishes, have no molars, the front of the jaws being occupied by incisors, which are often serrated, loosely attached, and movable. The numerous species are found in the warm seas and are chiefly herbivorous. [Illustration: FIG. 288.—Chopa or Rudder-fish, _Kyphosus sectatrix_ (Linnæus). Wood's Hole, Mass. ]