114 NATURAL SCIENCE. Feb.. 



the flint implements found in a sea-worn cave, of raised beach 

 horizon, high up the lofty cliffs east of Grosnez Point. This 

 continental period coming to an end in early historic time, the carving 

 work of the sea has practically but recently recommenced, and at a 

 much lower level than formerly. 



Entirely different is the case of those dykes that lie more or 

 less parallel with the coast. Locally known as " gutters," these 

 form systems of canals which, in connection with the dykes at right 

 angles to the shore line, are the potent factors that determine the 

 breaking up of the rock area into innumerable minor reefs and islets. 

 These gutters, humanly speaking, are veritable death-traps. The 

 unwary, penetrating far sea-wards in search of fish or the harvest of 

 wrack, often have their retreat cut off by the filling of these natural 

 ditches long before they become aware of the fact. So constant, 

 indeed, is this danger, that watch-boats. State-paid, hover, during 

 the wracking season, around and among the more dangerous reefs. 



Gutters have two very divergent faunas. Where the channels 

 are wide and sandy-bottomed, communicating freely with open water 

 at either end, banks of green, waving, grass-like Zostera — luxuriant 

 sea-meadows — make good the footing, binding the sandy bottom into 

 stable ridges. Such may be termed " canal gutters," as distinguished 

 from the " drainage gutters " that carry off the water from the higher 

 parts of the reefs as the tide runs down. Of the two, the former are 

 the poorer in faunal diversity — but withal they are wonderfully rich. 

 Upon the leafy blades of the Zostera, zoophytes occur in myriads. 

 Campanularia angulata disputes place with the feathery Plumnlavia 

 similis and with the graceful Clytia johnstoni. And upon these in turn, 

 at certain seasons, brown hosts of diatoms descend in enveloping 

 swathes. Haliclysius, also, often decks the green blades with its 

 lovely brown bells. Soft gelatinous compound x\scidians [Aplidium 

 gelatinosuin) also clothe the blades ; and in the breeding months of 

 spring, molluscan and annelidan spawn — Trochus, Nassa, Phyllodoce, 

 etc. — give diversity. The vivid green of the Zostera has had less 

 colour-influence upon its floating population than one would naturally 

 expect. I know of two animals only that are affected, but both are of 

 striking interest. One is the large emerald-hued Hippolyte viridis, 

 most lovely of the Prawns ; the other, equally brightly-coloured, is a 

 species of the Labridae or Wrasses. 



Quite a distinct and characteristic fauna gathers at the base of 

 the Zostera stems, and upon their half-decayed remains. Most obvious 

 are colonies of the brilliant orange-red Ascidian, Botrylloides rubruni, 

 lying profusely about like tiny coral-beaded truncheons, beneath the 

 concealing tangle of green. Little less conspicuous, and growing' 

 together with the Botrylloides, are snowy-white delicate masses that 

 bespeak to the practised eye the endlessly branching calcareous 

 sponge, Ascaltis contovta. 



But, after all, interesting and varied as is the life that swarms 



