hi 



prong to the petrosal ; they coalesce posteriorly at an acute angle, to form a slightly n- 

 |*mlrd due, from which the tfcond piece of the arch is suspended vertically. 



Ikit second piece, called teupala (11), U a slender, straight, stylifonn bone, terminating in 

 a point brlow, and morticed into a groove on the upper and outer side of thr lower and prin- 

 cipal bone of the arch. 



The pointed upper extremity of thif bone, called the eoracoid (), projects behind thr 

 icapula and almost touches the suprascapula : below this part a broad angular plate of thr 

 eoracoid projects backwards and gives attachment to the radiated appendage of the arch : 

 the rest of the eoracoid bends inwards and forwards, gradually decreasing to a point, which 

 it connected by ligament to its fellow, and to the urobyal bone. The inner side of the cora- 

 coid is excavated, and its anterior margin folded inwards and backwards ; it is continued 

 above into the posterior angular process ; but in the rest of the eoracoid it U simply bent 

 upon thr inner concavity of the bone which, in the recent fish, lodges the anterior origin of 

 the great lateral muscle of the trunk. 



The branchial arches belong to the visceral skeleton and are five in number : the three first 

 consist, first, of a short piece below, the kypobrantlual (), directly articulated to the median 

 series of bones, called b*nbra*ckiaU ; next, of a long bent portion, the eeratobranehial (47 ), 

 grooved on its outer convex side for the branchial vessels, and supporting dentigerous tubercles 

 oo its inner side ; and, above, of a shorter, similarly formed piece, bent inwards and for- 

 wards, the fpihraiirfiial (). To the epibranchial of the second and third arches is attached 

 a shorter and broader bone, the pkaryngobranekial, or superior pharyiigral, which is beset 

 with teeth. The fourth arch consists of the ceratobranchial, the epibranchial. and the pha- 

 ryngobranchial pieces. The fifth arch (ib. ') consists simply of the ceratobranchial ele- 

 ment : it is expanded and beset with teeth : it has been termed the inferior pharyiigral bone 

 (at pkaryngit* in/Meur, Curier). 



149. The cranium, with the maxillary and mandibular arches and labial cartilages, 

 of a Cod-fish (Gadu morrkua). The suprascapular elements of the scapular 

 arch are also preserved. 



The general form of the cranium in this, as in most Osseous Fishes, is conical, the base 

 being behind, and perforated by the foramen magnum, the apex widely and deeply cleft 

 transversely by the aperture of the mouth : the orbits are lateral, large, and communicate 

 freely with one another ; and there are, also, two deep lateral fissures behind, called gill- 

 apertures, with a mechanism for opening and closing them supported by the branrliiostegal 

 rays and the opercular bones. Most of the bones of the skull present the squamous charac- 

 ter and mode of union, being flattened, thinned off, and overlapping one another like scales ; 

 and many of them are endowed with independent movement*. 



The principal cavities, which are formed by the assemblage of bones, which have been 

 specified in preceding preparations, are, the 'cranium,' lodging the brain and organs of 

 hearing; the 'orbital' and the 'nasal' foes*; the 'bnccal' and the 'branchial' canals. 

 These cavities are not so well defined as in the higher classes, and in no class is the exterior 



o2 



