412 



MUGILID^. 



eggs (month of February), arranged in a great many laminoe. They 

 have a separate opening immediately behind the vent. 



The air-bladder is large, simple, -with its membranes thin ; por- 

 tions of the abdominal muscles project into the lateral anterior part 

 of its cavity. 



Skeleton. — The form of the skiill is obtusely conical ; the bones 

 are well ossified, with the sutures between them conspicuous. The 

 upper surface of the head is broad and convex, with scarcely any 

 channels for the muciferous system. The hind part of the occipital 

 region is produced backwards, and deeply depressed below the level 

 of the crown ; it is provided with a high crest, the upper margin of 

 which is not elevated above the level of the frontal bones : there are 

 two pairs of lateral ridges ; the outer is very irregular, curved in a 

 5 -like line, its anterior convexity being above the orbit ; the inter- 

 mediate crest is transformed into a horizontal flexible and shghtly 

 dilated process of the paroccipital, extending backwards or between 

 the two branches of the suprascapula and to each side of the verte- 

 bral column. The lateral portions of the crown are impressed, each 

 impression being divided into an anterior and posterior portion by the 

 outer crest. There are two deep lateral incisions on each side behind 

 the upper angle of the orbit, separated from each other by a long pro- 

 cess of the postfrontal pointing outwards ; the posterior is formed by 

 a prominent portion of the epitympanic and by the postfrontal, and 

 filled up by muscles, whilst the anterior receives the hindmost infra- 

 orbital bone. Ethmoid broad, cartilaginous. Praefrontal rather small, 

 smaller than the turbinal ; turbinal bones broad, widely separate 

 from each other ; praeorbital subquadrangular, the other infraorbitals 

 feeble and veiy narrow. The maxillary is subcyHndrical, not dilated 

 at its extremity, slightly cv>-like curved : the intermaxillary has a 

 broad short triangular posterior process, and is somewhat dilated at 

 its extremity ; its anterior margin is provided with a series of seti- 

 form bony fringes. The articulary of the mandible is vertically 

 elevated, whilst the dentary is flattened into a horizontal broad lamella 

 with a sharp anterior margin ; the bony fibres of which it is com- 

 posed are more coherent than in the upper jaw. Vomer anchor- 

 shaped ; palatine feeble and very narrow. The form of the opercles 

 may be seen externally, and we only mention that the prffioperculum 

 is provided with a rudimentary muciferous channel. 



The suprascapula is composed of two processes, one being nearly 

 thrice as long as the other ; the scapula is very short ; cavity for the 

 pectoral muscles deep, not very broad ; xilna with a rather small 

 ovate foramen ; a wide slit between radius and humerus ; carpal bones 

 exceedingly short ; coracoid well developed. 



Pubic bones elongate, flat ; they are not in immediate connexion 

 with the humeral arch, but suspended from the coracoids by a liga- 

 ment which is fixed near the root of the fins. 



There are eleven abdominal and thirteen caudal vertehrce, the length 

 of the former portion of the vertebral column being to that of the 

 latter as 1 : 1-05. The vertebrae are slightly compressed, of mode- 



