496 



FISSIROSTRES FLACOURTIANCE.E. 



most important family of fishes ; and, therefore, we 

 shall have to give some account of it under the speci- 

 fic name, when we shall bring together the principal 

 genera, in order that we may give an. account of them 

 111 the shortest space possible. 



Flat-fish (Platoridecs). These are also very im- 

 portant fishes in an economical point of view, being 

 very abundant, readily caught, and much esteemed 

 for their wholesome and nutritious qualities. As there 

 is no scientific name generally used for them, we shall 

 give some notice of the principal genera and their 

 characters, in the article FLAT-FISH. 



Discobolus. This order has no general English 

 name ; and the scientific one is derived from the 

 peculiar form of the ventral fins, which form a disc 

 under the thorax. The order is not a numerous one ; 

 and the different species which compose it are more 

 curious than useful. Some account of them will be 

 found in the articles LEPADOGASTER, CYCLOPTERUS, 

 and ECHENEIS. 



MALACOPTERYGII APODA. Fishes of this order have 

 the ventral fins entirely wanting, and, therefore, they 

 are less fitted for ascending and descending in the 

 water than almost any other fish. They form but one 

 family, AnguilliJts, in all of which the body is elon- 

 gated. Notices of the principal genera will be found 

 in the articles ANGUILLA, EEL, SACCOPHARYNX, 

 GYMNOTUS, GYMNARCHUS, and the different subor- 

 dinate articles referred to from the one or the other 

 of these. 



LOPHOBRANCHII. Tliis is a small but a singular 

 order, the leading characters of which are, that the 

 jaws are complete, and free or articulated, though of 

 peculiar shape. Their principal character, and the 

 one after which they are named, is the structure of the 

 gills, which are not in regular fringes, like those of 

 the generality of fishes, but formed into a sort of tuft, 

 which are placed in pairs upon the branchial arches, 

 and each individual fibre is divided or toothed, some- 

 thing in the form of a comb. These gills are attached 

 to a large gill-lid, but there is only a small hole for 

 the escape of the water. Their bodies are in general 

 covered with a coat of mail consisting of scaly pieces ; 

 they are generally of small size, and their bodies con- 

 tain little or no flesh. There are only two leading 

 genera, Syngnathus and Pegasus, under which name 

 some account of those very singular fishes will be 

 found. From the singularity of their forms, they are 

 called sea-needles, sea-horses, and a number of other 

 names. 



PLECTOGNATHES. These form the last order of 

 bony fishes, and make a very near approach to the 

 cartilaginous ones. The name of the order, as every 

 one knows, signifies that the different bones of the 

 jaws are soldered or united to each other. This dis- 

 tinguishing character is having the maxillary and 

 intermaxillary bones united to each other, and the 

 whole of the palatal arch attached in like manner to 

 the bones of the cranium ; but the whole of the bones 

 are soft and flexible, intermediate between the rest of 

 the bony fishes and the cartilaginous ones. The gill- 

 lids are little else than thick skin ; and the gill-open- 

 ings are merely slits. The true ventral fins are 

 entirely wanting. Cuvier divides them into two fami- 

 lies which are exceedingly natural, Gynmodontes, and 

 Sc/erodermes, which are named from the peculiar way 

 in which the jaws are armed, and of which some ac- 

 count will be found under those titles. Generally 

 speaking, they are fishes of very singular form, proba- 

 bly the most so of any of the finny tribe. Such is a 



very short outline of the systematic arrangement of 

 fish by the illustrious Cuvier; and with which we shall 

 close our desultory notice of this highly interesting, 

 and truly valuable class of animals. 



FISSIROSTRES (Open-billed birds], one of the 

 sub-orders, or families, into which Cuvier divides the 

 great order Passcres. Its general relation to the class 

 will be seen by referring to the article BIRD. It is 

 rather a small family, but the characters of the birds 

 which compose it are peculiar. The bill is short, very 

 broad, flat, slightly curved, and deep in the gape, and 

 the tomia do not meet at the sides. The bill is with- 

 out any notch in the mandible, which is the chief 

 distinction between these birds and some of the fly- 

 catchers. They feed wholly upon insects, and are 

 migratory. There are only two distinct divisions : 

 day-feeders, which form the different swallows and 

 swifts ; and night-feeders, which comprises the 

 birds usually termed goastuckers. Some of the 

 details will be found in the articles GOATSUCKER and 

 SWALLOW. 



FISSURELLA (Lamarck ; PATELLA, Linnteus). 

 This shell exhibits a very striking illustration of the 

 wisdom of the present system of classification, since 

 it differs in many important features from the patella, 

 with which Linnaeus had confounded it ; taking in 

 this, as in every other instance, the form of the shell, 

 without any reference to its parent architect. Shells 

 of this genus are in the form of a very depressed 

 truncated cone, oblong or elliptical, and perforated 

 at the summit, vertically towards the anterior part ; 

 the orifice is in connection with the animal's mantle, 

 and never quite circular, but more frequently long, and 

 oval-shaped, and sometimes resembling a key-hole, 

 whence they are familiarly called key-hole limpets. 

 The margin of the shell is thickened, and sometimes 

 crenulated, and the exterior surface longitudinally 

 ribbed, and sometimes striated transversely. There 

 are numerous species of this mollusc : they will admit 

 of a better defined arrangement than now exists. 



FISTULANA (Lamarck.) All former natural- 

 ists considered these tubes, like those of the Asper- 

 gillum and Clavagella, which enclose and protect the 

 animal, to be the shells themselves, but it is now 

 satisfactorily ascertained that they are quite distinct, 

 that genus having their shell free and detached within 

 the sheath or external tube. This shell is bivalve, 

 and neither of its valves fixed into the partition of 

 the tube, which is generally testaceous, closed, and 

 retort-shaped at the anterior end, attenuated towards 

 the other extremity, where it is open. If the shell 

 contained have its valves similar, but not closing 

 together, they are what is termed gaping. The pos- 

 terior open extremity is divided by a thin partition, 

 forming internally two channels or siphons. 



The animal greatly resembles that of the teredo, 

 but is in general shorter and more club-shaped, and 

 a great diversity of opinion exists as to the propriety 

 of separating this genus from that, since it I as been 

 asserted that the Fistukma has been found embedded 

 in wood, which it was not supposed capable of effect- 

 ing, and therefore a good ground for constituting a 

 new genus. Two fossil species are known. 



FISTULARIA. See PIPE FISH. 



FLACOURTIANCE^E is a small natural order of 

 equatorial shrubs or small trees, with alternate exsti- 

 pulate, simple leaves, shortly petiolated, often entire, 

 and coriaceous : flowers are axillary, solitary, or con- 

 gested, and they are regular and usually united, 

 but sometimes separate by abortion. The calyx is 



