302 LIFE BY THE SEASHORE. 



sight to be very different from that of the saithe, and is apt 

 to be a little puzzling. If the saithe be carefully examined, 

 it will be seen that the operculum consists of a flat hard 

 plate, fringed at the edge with a soft membrane supported 

 by some inconspicuous rays of cartilage, the whole lying 

 close to the lateral body-wall. In Coitus, on the other hand, 

 the soft membrane is greatly expanded, and is supported by 

 a number of long distinct rays, curved so as to leave a con- 

 siderable space between them and the underlying gills. If 

 you seize a living Coitus, you will find that it is capable of 

 greatly increasing this space by raising these rays and their 

 membrane (the branchiostegal or gill-cover membrane), so as 

 to greatly increase the width of the head. As the head 

 swells the spines are erected, so as to make the Coitus an 

 ugly mouthful. There can be no doubt that this must 

 protect the fish against attack, for there are not a few stories 

 of birds found choked by getting the distended head with 

 its sharp spines fixed in the throat. If you compare the 

 ugly "bullhead" with the saithe, you will notice at once 

 how much the misshapen head takes off from the graceful 

 fish shape, as it must also diminish the swiftness of motion, 

 but great swiftness is probably not necessary to a rock- 

 haunting form, and the shape fits it for a life among rocks 

 and weed. 



As to the other characters, we may notice that the 

 pectoral fins are large and fan-like, accentuating the size of 

 the anterior region of the body, while the ventrals are small 

 and inconspicuous. There are two dorsals and one anal fin, 

 and the tail fin is simply rounded and not cleft. There is 

 no marked distinction in colour between the two forms, the 

 general tint in both cases being brown or greyish green, 

 prettily marked and banded with dark brown or black. In 

 the sea-scorpion the under surface is pale, or sometimes 

 yellow, with strong dark markings. There is no great diffi- 

 culty in distinguishing the two species. In Coitus scorpius, 

 the larger, the preoperculum bears two spines, the upper 

 and longer of which is less than the diameter of the eyes; 

 the first dorsal fin has nine to ten rays, the second thirteen 

 to fourteen, and the anal nine to thirteen. In Coitus bulalis 

 the preoperculum bears four spines, of which the uppermost 

 and longest is longer than the diameter of the eyes, and the 



