64 WITH HARD CHEEKS. 



the receding tide in small pools among rocks. When touch- 

 ed, it distends its gill-covers, and sets out its numerous 

 spines, assuming a most threatening appearance. This spe- 

 cies spawns in January, and the ova at that time are very 

 large, and of a fine orange yellow colour. These are de- 

 posited near the sea-shore, frequently in the estuaries, and 

 sometimes even in rivers ; the fish having prepared itself 

 for this change by its previous residence in the brackish 

 water, after which it appears to be able to bear either ex- 

 treme. Its food is small crustaceous animals, and it is said 

 to be particularly partial to feeding on the fry of the 

 Blennies. 



D. 8 12 : P. 16 : V. 1+3 : A. 9 : C. 10. 



In Coitus bubalis the space between the eyes is much 

 narrower than in the C. scorpius ; the eyes in position more 

 vertical, the crest above the eyes on each side more elevated, 

 nearly straight, and ending at the nape in a spine directed 

 backwards, forming a pair of occipital spines ; irides yellow, 

 pupils black : preoperculum with four spines, the upper 

 one the longest ; operculum with three spines, besides the 

 scapular, clavicular, and nasal spines, similar to those of 

 C. scorpius : gill-openings large ; in general colour very 

 similar to that last described, and both species exhibit 

 occasional variations in the intensity of the red and brown 

 tints ; lateral line rough : the ventral fins in this species 

 are devoid of the connecting membrane observable in C. 

 scorpius. 



Some circumstances observable in the economy of this 

 species lead to the introduction here of a few observa- 

 tions on the respiration of fishes, in reference to their power 

 of sustaining life when taken out of the water, and its 

 supposed connexion with the size of the gill-aperture. 



