CRUSTACEANS 



records claim only one. An excellent guide to Hunstanton and its 

 Neighbourhood, by Philip Wilson, seventh edition, revised and greatly 

 enlarged, etc., by George Webster, 1881, in the copious natural 

 history, though it speaks of ' the crab-sea,' mentions no crab, and only 

 one solitary crustacean. This is entered under the heading of conchology, 

 and named 'Common Acorn-shell {Lepas balanus).' The account given 

 of it is w^orth quoting : ' Very abundant on the large boulders of black 

 rock scattered along the shore. The little animal inhabiting this multi- 

 valve will afford the observer a spectacle of great interest. Let him find 

 one of these acorn-shells on a small detached piece of rock, and keep it 

 from moisture for an hour or so, till it becomes perfectly dry ; then place 

 it in a basin of sea vv^ater, when it will open the valves of its abode and 

 exhibit its beautiful plume-like processes ; these are the tentacula of the 

 animal, with which it procures its food, and which it waves backwards 

 and forwards in a most graceful manner.' ^ All this is much to the 

 purpose for those who wish to be amused by a pleasing sight, and do not 

 care to be troubled with scientific technicalities. But it is strange that 

 in 188 1 a writer on natural history should still be classifying the 

 crustacean cirripedes among the Mollusca. It is equally strange that one 

 of Charles Darwin's fellow-countrymen should at that date be placidly 

 using such a name as Lepas balanus to distinguish a sessile cirripede 

 species. As most naturalists are perfectly well aware, Darwin devoted 

 several laborious years to the elucidation of this group, and wrote a 

 monograph upon it in two large volumes, published by the Ray Society, 

 one volume describing the Balanidae, the other the Lepadidse. The 

 most casual glance into this standard work would have saved the situation 

 for the Hunstanton Guide. The trivial name of acorn-shell unluckily has 

 been applied to members of both families, but species of Lepas are easily 

 distinguished by their leathery stalk from species of Balanus, which have 

 no stalk, but are firmly seated on the rock or other basis of support. 

 It is evidently not to a Lepas but to one or other of the rock-coating 

 species of Balanus that the Guide refers. The plumose tentacula spoken 

 of are in fact the animal's legs, their waving hairs producing an 

 appearance of ringlets {cirri), from which the name of Cirripedia is 

 derived. The more recent alternative name, Thyrostraca, or door-shells, 

 refers to the valves, the opening and shutting of which for emission or 

 withdrawal of the cirri is an attractive sight to every new observer. 



Faunistic catalogues for areas that are not exceptional are not 

 always highly prized by working naturalists, but the great forest of sea- 

 weed which Frank Buckland speaks of as existing off the north coast of 

 the county might well be made the subject of special exploration. 

 Almost certainly in skilful hands it would largely extend our knowledge 

 of the marine Crustacea of Norfolk. 



* Hunstanton Guide, p. 68. 



199 



