2750 THE BONY FISHES AND GANOIDS 



that hang like grape clusters within its orbicular case; and M. Vaillant has shown 

 that each nest is made of one seaweed, the different twigs being brought together 

 and made fast to each other by the fish by means of a pasty sort of substance 

 provided by the animal itself. ' ' 



THE BULLHEADS AND GURNARDS Family 



The thirteenth family of the present section differs from all the foregoing, with 

 the exception of the genus Pseudochromis and its allies, in the presence of a bony 

 process arising from the infraorbital ring of the skull to connect it with the spine 

 at the angle of the preopercular bone. In shape the body is more or less elongate 

 and subcylindrical; the cleft of the mouth is transverse, and the weak teeth are gen- 

 erally arranged in villiform bands. As a rule, there are two dorsal fins, of which 

 the spinous is less developed than the soft; both the latter and the anal being elon- 

 gated; the pectorals may be provided with filamentous appendages, and the pelvic 

 pair have not more than five rays. The body may be either naked, scaled, or pro- 

 tected by a single row of plate-like scales. The members of this family, which 

 are arranged under a good many generic heads, are distributed over almost all seas> 

 while a few inhabit fresh waters. Of comparatively-small or medium size, these 

 fishes have but poorly developed swimming powers, and spend their time swimming 

 or crawling at the bottom of the sea in shallow water at no great distance from the 

 coast. A Japanese bullhead is stated, however, to have been dredged in five 

 hundred fathoms of water. In a fossil state gurnards referable to the existing genus 

 occur in many of the European Tertiary rocks; while remains of bullheads are met 

 with in the upper Miocene of Basle, and those of the allied extinct genus (Lepido- 

 cottus), distinguished by its ctenoid scales, in the upper Eocene of Switzerland. 



The familiar bullhead or miller's thumb (Cottus gobio) of the 

 streams of Britain and many other parts of Europe, belongs to a genus, 

 containing some forty species, mostly distributed over the fiesh waters and coasts, 

 of the temperate zone of the Northern Hemisphere. All are of small size, and 

 characterized by the broad, depressed, and rounded heads; the subcylindrical body, 

 somewhat compressed posteriorly; the absence of scales; the distinct lateral line; 

 and the rounded pectoral fins, in which some or all of the rays are simple. Villi- 

 form teeth are present on the jaws and vomer, although there are none on the pala- 

 tine bones. In the majority of the fresh- water species the spine on the preopercular 

 bone is simple, but becomes branched in many of the marine forms. The common 

 fresh-water species, which ranges over Central and Northern Europe to Northern 

 Asia, seldom exceeds four or five inches in length, and is more generally found in 

 small streams than in large rivers. It has a well-known habit of concealing its- 

 broad and flat head beneath loose stones on the river bottom, and in this position 

 will lie motionless for hours, but when disturbed swims swiftly away. Its food 

 consists of the larvae of water insects and crustaceans, as well as the eggs and fry 

 of other small fish. The other British representatives of the genus are all marine, 

 and include the sea scorpion (C. scorpius) and father-lasher (C. bubalis), both of 



