• iNdMdUI'llolS FISHES. 



46.^ 



<;ill-openings large; bruncliiostegal 

 membranes united to each otlier to 

 a greater or less extent anil free from 

 tlie istlimus. 



«; Anterior part of tlic 'lorsal lln- 

 system separated into a distinct 



(in, or at least with the anterior 



rays elongated. Fani. Maa-uvulw. 



(i: No distinct anterior dorsal fin Fam. Opltidiidfj;. 



/'.- ( iili-openings small; brancliiostegal 

 membranes united by the skin of the 

 body into a broad isthmus Fam. Lijcodidw. 



Fam GADID^. 



rSodi/ cldiK/atrd, ciDiipresscd, daratc or fitsifonn, and ctni'icd trill/ thin cycloid sccdes. Ctiudul Jin distinct from 

 flic other rcrticdl tins", ./airs fiiniislicd iritli tciili. dill-opi'tiiiif/s lari/c: Jiraiicliiostegal mcnil/raiics more or less 

 complefeli/ free from the isthmus. I'seiidoliraiichio' traiitintj, or i/laiidiilar. Air-hladder and jn/loric aj)))endages 



f/encralli/ ireU-dcvclopeci. 



The Cocl-f;imily contains numerous forms: about 

 80 species, distributed among 25 genera, are known at 

 present*. Almost all these forms are marine fishes, but 

 the well-known Bnrbot-geuus lives in fresh or brackish 

 water. A great part of the mai-ine fishes are deep-sea 

 forms, properly so called, some of them descending to 

 de])ths of about "2,000 fathoms, and all of them, like 

 other forms of this nature, probably having a wide geo- 

 graphical range, even between the Tropics. The rest 

 of the family, which frequent water of less depth, from 

 the surface down to a depth of about 300 fathoms — 

 though some of them have been found in 600 fathoms 

 of water — are, almost all, inhalaitants of the Frigid 

 and Temperate Zones, only one genus belonging to the 

 surface regions of the Tropics'. The development of 

 the family is incomparably more diversified in the north- 

 ern seas than elsewhere, and there the Cod-fishery has 

 long been one of the most lucrative to the fishermen 

 of many nations. 



( )f tlie peculiarities of the skeleton we have already 

 remarked, in a com]jarison between this family and the 

 preceding one, the lobate process on the upper (poste- 

 rior) side of the intermaxillary bones, ^vhich in the 

 Codfishes is especially well-developed, and generally 

 renders these bones so easily recognisable (fig. 118, /). 

 The nasal process {ii) of these bones, on the other hand, 

 is short, the snout being only slightly, if at all pro- 

 trusile. The cephalic system of the lateral Hue is fur- 

 nished with well-developed ducts and cavities in the 



region we are ])artieularly struck by the wide expansion 

 of the styloid bone (opisthoticum), the lionc with which 

 the anterior end of the lower branch of tlie posttem- 

 poral I)one articulates or coalesces, and which in this 

 series is generally larger than the petrosal bone (jiro- 

 oticum) in front of it, or at least equal in size to tlie 

 latter. The ventral fins are suspended from the inner 

 surface of the anterior part of the clavicle by the an- 

 terior end of the pelvic bones. The vertebra; of the 



Fig. 118. Intermaxillary bones of the Polar Cod (Gadus saida), 

 niagn. 2 diain. 1, 3, 5, and 7 from a specimen 20.5 mm. long, from 

 the White Sea; 2, 4, 6, and 8 from the Glacial clay at Lomma 

 (Scania). 1 and 2 seen from the outside, 3 and 4 from the inside, 

 5 and () from above, 7 and 8 from below. /, the lobate process; 

 /(, tlic nasal process; ai; the articular process. 



* 



body are characterized by the marked and often singular 

 development of their transverse processes. The first two 

 vertebrae are generally without ribs; the first of all is 

 often firmly united by its body and neural arch to the 

 occipital bone. The following (2 — .5, generally 4) ver- 

 tebra? are furnished with terete, wand-like ribs, curved 

 as in the Cod, or straight as in the Hake, and articul- 

 bones belonging to the dermo-skeleton. In the occipital j ating in distinct articular cavities with the bodies of 



" Striiisia tinea, an imperfectly known Mediterranean tish, described and figured by Bonaparte as having confluent vertical fins, is 

 generally included among tlie Gadidte. hut is referred by tlie characters mentioned above to the family Macrurida, if it does not indeed 

 turn out to be identical with Uralcptus Maraldi, a Gadoid tish with distinct caudal fin. 



'' In .JonriAN and GiiiiKirr's statement of 35 genera with about 90 species GuNrnEB's subfamily Brotulina of the family Optiidiidce 

 is included. 



■-" Bregmaceros, willi two .species from India, New Zealand, the Philippine Islands, and China, as well as from the depths of the Gulf 

 of Mexico. 



