From the second edition (1989):
(ˈhʊklɪt) [f. as prec. + -let.]

A small or minute hook; esp. in Nat. Hist.

1836–9 Todd Cycl. Anat. II. 127/1 Hard transparent horny hooklets around the oral proboscis. 1872 Nicholson Palæont. 314 The spines, or hooklets, or denticles of Naked Molluscs and Annelides. 1897 Allbutt Syst. Med. II. 1007 The suckers and hooklets serve to attach the parasite to the mucous membrane of the alimentary canal of the host.