CRUSTACEANS 



the Medway." The sunfish, which is now called Orthagonscus mola, is 

 a little paradise for parasites, but also the Right Whale carries its 

 amphipod Cyamus, the carp its branchiopod Argulus, the sturgeon its 

 strange-looking copepod Dichelestium, and so on through the list might 

 be mentioned one eccentric form after another, which is only waiting 

 for a chronicler to give it the right of taking its place in the Kentish 

 fauna. 



Something still remains to be said of the Thyrostraca, better known 

 as cirripedes and better still as barnacles, if betterness of knowledge can 

 be reckoned by the familiarity of a name. Of the sessile species the 

 county may at least claim Darwin's Balanus improvisus, since he says of 

 it, • This species, as far as my experience goes, is commoner on the 

 shores of Kent than on other parts of England : the first specimens 

 which I met with, I owed to the kindness of Mr. Metcalf ; they were 

 attached to wooden stakes from Heme Bay, together with a single 

 specimen of B. crenatus : I have seen other specimens from near 

 Woolwich, from the Kentish oyster-beds, from Sandwich and from 

 Ramsgate. . , . This species is often attached to wood. At Ramsgate, 

 the specimens were attached to a small coasting vessel, and they must 

 have been immersed five or six feet ; they were associated with B. 

 crenatus^ and with a few of B. balamides.^ At Monte Video Darwin 

 found this species capable of living in water perfectly fresh, with a 

 chance at high tide of having a bath in slightly brackish water. He 

 remarks on the singularity of a species capable of living in fresh water 

 and likewise in the saltest seas, when ' even brackish water is a deadly 

 poison to several, probably to most, species of the genus.'* Of B. 

 crenatus, Bruguiere, Darwin says : ' I have received specimens from all 

 parts of the coast of Great Britain and Ireland, generally attached to 

 Crustacea and moUusca, and never hitherto from rocks uncovered by the 

 tide. ... At Ramsgate, in Kent, I saw a rudder of a ship, in which 

 the two or three upper feet were thickly coated with B. balanoides, and 

 the two or three lower feet with B. crenatus and improvisus mingled, 

 together with a few of B. balanoides.'^ This latter species often crowds 

 the shore between extreme tide-marks, but Darwin doubts whether it 

 ever lives below the lowest ebb.* He also points out that ' When a 

 specimen is disarticulated, our present species can at once be dis- 

 tinguished from B. cre?:atus (and from B. improvisus) by its membranous 

 basis, and by the solid or cancellated walls, which are rarely permeated 

 by regular tubes or pores ; and the walls when porose are not internally 

 ribbed.'* From B. crenatus the species B. improvisus is distinguished 

 externally by having the edges of the radii ' much smoother and 

 rounded, and the whole shell less rugged, internally by the porose basis, 

 the presence of an adductor ridge on the under side of the scutum, and 

 the graduated teeth on each side of the central notch in the labrum.' ' 



' England's Topographer, i. 105 (1828) ; ii. 586 (1829) ; iii. 696 (1829). 

 3 Monograph of the Balanidae, 252 (Ray Soc. 1854). ' Loc. cit. 264. 



* Loc. cit. 272. » Loc. cit. 271. • Loc. cit. 265. 



261 



