236 Mr. Yarrell on the Anatomy of the Corvorant. 



of this bone to its lateral angle throughout its whole length from the 

 extreme point to the occiput^ there arises on each side a triangular-shaped 

 long muscle, the fibres of which are directed forwards, downwards and 

 outwards to be inserted by a strong tendon upon the upper edge of the lower 

 mandible, immediately behind the the insertion of the tendon of the 

 temporal muscle. The muscles of the upper part of the neck, giving 

 motion to the head, are inserted upon the occipital bone and its elevated 

 crest, over which these additional muscles slide with every movement of 

 the head, the particular articulation of the xiphoid bone only permitting 

 it to become a fixed point of support to its own particular muscles, when 

 both act simultaneously as additional elevators of the lower mandible, thus 

 assisting in prehension, and materially increasing the power of the bird in 

 securing a slippery prey. I may here also observe that the various other 

 species of fish-feeding birds before referred to as having their lower mandi- 

 bles so much stouter and stronger than the Corvorant, have also much 

 deeper yb55<E and more elevated ridges for the origin and attachment of their 

 temporal muscles, and are in this way the better able to prevent the escape 

 of their natural food, without the additional muscles of the Corvorant. 



From these comparative remarks it will be perceived that the Corvo- 

 rant does not possess the same strength of bone in the mandibles with the 

 ♦other oceanic fish feeders, though not less inclined than they are to pursue 

 and take fish of large size. The dilatation of which the lower mandible is 

 capable from its elasticity, the length and freedom of motion of the ossa 

 quadratay the great size of the (Esophagus which when distended measures 

 10 inches in circumference, all afford facilities for the swallowing of prey, 

 which, but for his additional muscles he would probably be unable to 

 hold. This peculiarity of structure is most likely te be found in other 

 species of the genus Pelecanus, but it is only in our common Corvorant 

 that I have had opportunities of ascertaining the fact. 



One misfortune attending the promulgation of error is, that the evil 

 increases in exact proportion to the weight of the authority with whom the 

 mistake originates ; and if any apology be considered necessary for thus 

 occupying a portion of the Zoological Journal with a description and 

 representations of a small part only of the anatomy of so common a bird 

 as the Corvorant, I trust that apology and excuse will be found in the 

 following quotations; and that the view of the structure and its uses 



