490 TELEOSTEI [CH. 



In spite of the enormous toll on its numbers levied by the fisheries 

 of Northern Europe it appears to be actually on the increase. The 

 Pilchard is a smaller fish which lays floating eggs as does also the 

 Anchovy. The true or French Sardine is the young Pilchard. 

 Whitebait consists of the fry of the Herring. 



The Salmonidae are distinguished by having a small fin-fold 

 devoid of rays (the adipose fin) behind the dorsal fin. The air- 

 bladder is a simple sac and the oviducts are very short tubes 

 unconnected with the ovary. 



The genus Salmo includes the Salmon and Trout. Salvelinus is 

 the Char (called the Trout in America) and Coregonus is called the 

 White-fish in America and by various names in England. Salmon 

 and Trout are well known as sporting fish in this country, they are 

 esteemed as delicacies for the table but do not furnish a source 

 of food comparable in importance with the Herring. But on the 

 Pacific coast of America, allied genera are netted in enormous 

 numbers, and their flesh packed in tins is sent all over the world. 

 All the Salmonidae spawn in fresh water and the young fish passes 

 one or two years in fresh water before going to the sea, and may 

 (as in River Trout) pass all its life there. It is to be concluded that 

 the Salmonidae furnish a rare instance of a family of fish primitively 

 fresh -water, some species of which have regained the sea and are 

 able to maintain themselves there. Coregonus, the White-fish of 

 the great lakes of America and the " Pollan " of Lough Neagh in 

 Ireland, is much esteemed for the delicacy of its flavour. 



The sub-order ANGUILLIFORMES includes the Eels. In these fish 

 the caudal and pelvic fins are lost, and the dorsal and anal fins 

 have extended till they meet at the extremity of the tail and form 

 a continuous fringe round the hinder end of the body. In this 

 way a tail fin is produced which resembles that of the larva, but 

 its apparent primitive character is due to secondary degeneration. 

 Such a tail fin is called gephyro cereal. Scales are reduced to 

 vestiges deeply embedded or are absent altogether. The air-bladder 

 has a duct, and the oviducts as in the Sahnonidae are represented 

 only by abdominal pores. 



In the skull the cranium is not narrowed between the orbits, 

 the premaxilla and in some cases the maxilla is lost, and the 

 symplectic is not developed, since the hyomandibular bone is joined 

 directly to the quadrata. The pectoral girdle is no longer con- 

 nected with the skull, the post-temporal bone being absent. Some 

 fish belonging to this group, such 'as the common Eel, live partly 



