CHIM^ERID^E. 287 



longer than the body. Scales very minute in the young along the back, bnt 

 absent in the full grown. Colours are said to be of great beauty when newly 

 eaptui*ed, so much so that the Norwegians term it the gold and silver fish. 



Name. King of the Herrings, rabbit-fish, Zetland. Pontoppidan tells us that, 

 from the length and form of its tail, this fish is sometimes called the sea rat. 



Habits. These are but little known. Sometimes, at least, it must be a deep- 

 sea form, as a young one was obtained in the voyage of the " Knight Errant " at 

 555 fathoms depth. It is generally supposed to feed upon small fishes ; Bloch, 

 however, considei-ed that it consumes crustaceans and medusas. 



Modes of capture. Said to be usually taken while in pursuit of shoals of 

 herrings or other fishes. 



As food. Its flesh is hard and coarse. 



Uses. Norwegians are said to extract an oil from its liver, which is highly 

 prized for treating some disorders of the eyes, and also, according to Pontoppidan, 

 for all wounds and bruises. 



Breeding. Eggs large and covered with a horny shell, flattened on the edges 

 and velvety. 



Habitat. Coasts of Europe, as indicated under the head of the geographical 

 distribution of the genus. Has been taken in Zetland (Fleming), and also in 

 the Orkneys (W. Baikie), while off Banffshire one has been secured when floating, 

 but dead (Edward). Attains to 3 or 4 ft. in length. The one figured was from 

 a male specimen in the National collection. 



Sub-Order II-PLAGIOSTOMATA. 



Body more or less cylindrical or depressed : the trunk may or may not 

 pass gradually into the tail. From five to seven external gill-openings, which 

 may be lateral or inferior. Jaws distinct from the skull. 



In these fishes the gills are not situated in a common cavity, but in separate 

 sacs which do not communicate one with another. In those forms possessing 

 five sacs the four anterior ones are lined in front with parallel rows of adherent gills, 

 while in the fifth only it has three processes solely in its proximal side. Water 

 for respiratory purposes is taken in by the mouth, and passes through pharyngo- 

 branchial slits into these sacs, from whence it passes out externally through the 

 external gill-openings or stigmata. The scapular arch, which is suspended to 

 the front part of the vertebral column, divides these respiratory sacs from the 

 cavity of the abdomen. Although no opercular pieces exist, there are sometimes 

 cartilaginous rings surrounding the gill-openings. 



The fishes of this sub-order have been divided as follows : 



Group I Selachoidei. Sharks. The trunk gradually passing into the tail. 

 Gill-openings lateral. 



Group II Batoidei. Skates and rays. Gill-openings ventral. Pectoral 

 fins largely developed and constituting a flat disc. 



Group I Selachoidei, as defined above. This group has been sub-divided into 

 several families, representatives of five of which have been taken on our shores. 

 They are as follows : 



Family I Cakchariid^;. Two dorsal fins and one anal. Eye with nictitating 

 membrane. 



Family II Lamnid;e. Two dorsal fins and one anal. Eye without nictitating 

 membrane. 



Family III Notidanid^;. One dorsal fin and one anal. Eye without 

 nictitating membrane. 



Family IV Scylliim:. Two dorsal fins, one anal. Eye without nictitating 

 membrane. Teeth small, and in several rows. 



Family V Spinacid^;. Two dorsal fins, no anal. 



The sharks found off our shores chiefly consist of true sharks, dog-fishes, and 

 the hammer-headed forms : some being residents or summer visitants, while a 



