176 THE VICTORIAN NATURALIST. 



form an " operculum." His mouth is not on the front border oi 

 the head, but on its under surface, hidden away as if to suggest to 

 the world at large that he really has not got a mouth at all, you 

 know. Thus when a shark turns it means more than when the 

 worm does. His skeleton is not bony but cartilaginous, and 

 thus the suppleness of his long body is secured, while his two 

 pairs of fins are relatively larger and stouter than those of his 

 neighbours, and worked by formidable batteries of muscles. 

 His cerebellum is large, and, in consequence, he can deftly steer 

 and dexterously regulate his movements. The lobes of his tail- 

 fin are very markedly unequal, and if he has scales they are 

 tubercular or spiny, and scattered in their arrangement. 



The rays are closely allied to the sharks, but are adapted for 

 life on the sea bottom, and flattened horizontally. The head is 

 very wide from side to side, and the five gill-slits accordingly 

 appear on the under surface. 



Owing to their great swimming powers, which renders dis- 

 persion easy, and also to their antiquity — for their pedigree can be 

 traced back to early geological periods — the distribution of sharks 

 is world-wide. The larger forms abound in the tropics, as a rule, 

 and hence everyone knows the danger of bathing in the Caribbean 

 or the South Seas, but the smaller forms abound in temperate 

 regions, and it is true, though not a matter of alarm, that the 

 shores of England are beset with millions of sharks, which 

 swarm in her waters. 



Even some of the species are world-wide in their distribution. 

 In November, 1883, I was attracted by a placard in Swanston- 

 street, announcing that a huge shark, 36 feet long, was on view 

 within. It was a Basking Shark (Selache maxima). It had 

 never previously been met with out of the Northern Hemisphere. 

 In all probabihty this individual shark was captured in the middle 

 of a voyage round the world, which recalls the daring and fili- 

 bustering expeditions of Drake and his comrades. Another 

 solitary visitor from European Seas, a specimen of the Spiny 

 Shark ( Echinorhhms spmosus), was captured at Portland in 

 November, 1886, and has been secured by Professor M'Coy, and 

 can be seen, beautifully mounted, at the museum. In an adjoin- 

 ing part of the building is a European specimen, with which our 

 strayed one may be compared. One cannot say that he seems to 

 have suffered in the globe-trotting. In neither of these cases has 

 a second individual, apparently, been detected in Australian seas. 

 But single specimens of each have smcebeen taken off New Zealand. 

 One of the terrible Carcharius ?nelanopterus, allied to the " Blue 

 Shark " of European seas, a fellow 15 feet in length, and with 112 

 serrated teeth, is recorded from Hobson's Bay by Professor M'Coy. 

 He had probably strayed from the North. The form is common 

 in Torres Straits and off North Australia. The Blue Shark itself, 

 singularly enough, is common in Port Arthur, Tasmania. It does 



