450 Scientific Proceedings^ Royal Dublin Society. 



number of these fish oif the Mayo Coast from the Captain of H.M.S. " Grappler" a 

 short time afterwards. On the 4th May the Inishkeagh Islanders told us that sharks 

 had been about for some days, the last haying been seen a few hours before our arrival 

 from the South. At Gola Island none seemed to have been observed when we visited 

 it on the 26th of May, and we failed to hear of them further north. It may be 

 remarked incidentally that the Gola Islanders, at any rate, do not seem to distinguish 

 between this fish and the KiUer or Grampus. ^ At least such was my impression after 

 questioning the Gola pilot about the latter, two specimens of which were in sight at 

 the time. I was convinced that some of his remarks about these cetaceans referred 

 really to the sharks, whilst others appeared appropriate to the subject. "Stinker" 

 is the not particularly euphonious name which is locally in use for the Killer, or 

 Basking Shark, or both. 



Sir Henry Gore-Booth, who accompanied us diu-ing our cruises about the Boffin 

 Islands after sharks, remained behind at Boffin, and killed two males during the middle 

 of May, and saw several others. 



The annual visits of this shark to the West Coast are matters of common knowledge. 

 It appears that they strike the coast, or are iixst seen, off the Aran Islands, about the 

 beginning of April, and are then said to pass north. At the end of April they are 

 looked for off the Boffin archipelago ; nowhere do they seem to stay for more than a 

 few days ; and it is a curious fact that the fii'st shoal, here at any rate, is always suc- 

 ceeded by what is supposed to be a second shoal some little time afterwards. Thus 

 the fish killed by the islanders of Shark this year was one of the first shoal, whilst 

 those killed by Sir H. Gore-Booth belonged to a later detachment. It is noticeable 

 that the first was a female, and the other males, but in the absence of any statistics of 

 the sex of fish killed in previous years, this affords no safe ground for conjecturing that 

 the females arrive before the males, and I merely throw out the suggestion in the hope 

 of attracting attention to the subject in future years. 



It is generally supposed, and with a fair show of evidence, that the fish pass north- 

 wards along the coast, past the Hebrides,- and so to Norway. 



As to the cause of this annual migration shorewards, we have no information. It 

 is similar in many points to that of the Mackerel, which is often attributed to the 

 spawning instinct. But Mackerel arrive on the coast long before they are ready to 

 spawn, but not before the minute organisms (Copepods), which certainly form a large 

 proportion of their food, have become plentiful in the coast waters ; and it appears to 

 me that spawning (if not only an incident of) is by no means the sole cause of their 

 arrival. So with our sharks. At the time they arrive off Boffin Mackerel are plentiful 

 there. So it follows, to the popular mind, that the shark pm-sues the Mackerel, Herrings, 

 &c., for predacious purposes. 



Day, after considering the structural evidence — the large size of the gill openings, 

 the small size of the teeth,- and the peculiar straining apparatus of the gill-arches, 

 together with such evidence as could be had on the contents of stomach after death, 

 concluded that this fish is " not a rapacious monster, but a devourer of minute animals, 

 and perhaps herbage." As to the latter, the evidence rests principally on Pennant's 

 diagnosis of " some green stuff, the half-digested parts of Algae, and the like," which 

 he found in the stomach of one. Several observers speak of a reddish fluid mass, and 

 such was present in the dead example which I examined at Shark Island, and in the 

 stomachs of the two killed by Sir Henry Gore-Booth. Sir Henry kindly sent me some 



1 Or ca gladiator (Lacep). 



~ It seems to me that the enormous gape is important evidence in the same direction 

 {cf. the Right Whale, &c.). 



