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.
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