1908- 1909.] Glimpses of Marine Life on the Forth. 117 



is a compound animal, consisting of a colony of very simply 

 organised individuals, whose wants are supplied by the currents 

 of water circulating through the interstices of its substance. 

 Sponges are not perhaps prepossessing objects, yet the skeleton 

 of one of the glassy sponges — the Venus' Flower - Basket 

 {Euplectella) — will compare for beauty with almost any of 

 Nature's productions. Its hollow cone, about a foot in length, 

 has a delicate framework composed of glassy fibres interwoven 

 in most graceful patterns. It comes from the Philippine 

 Islands. 



The lace-like incrustations seen on many sea-weeds are the 

 calcareous skeletons of species of Polyzoa, a family of com- 

 pound animals of much higher organisation than the sponges. 

 Membranipora occurs abundantly on the common tangle; in 

 the living state it forms a gelatinous layer, which the micro- 

 scope shows to be composed of large cells, each occupied by 

 an active little polype furnished with a wreath of tentacles. 

 Flustra, the sea-mat, easily mistaken for a sea-weed, is also 

 one of the Polyzoa. These animals are placed by some near 

 the ascidians, but the absence of a heart has led to their 

 being classed with the echinoderms and worms among the 

 Annuloida. The animals included in this class have unseg- 

 mented bodies, and are destitute of jointed limbs, but in the 

 next higher sub-kingdom, the Annulosa, the body is made up 

 of rings, and jointed appendages are always present. In- 

 cluded in this division are the Crustacea, a large family well 

 represented on our shores. Besides the common and Norway 

 lobsters we have the edible, the shore, the spider, the porcelain, 

 and the hermit crabs. In addition to the sandhopper we 

 have the smaller amphipod, Gammarus, plentiful everywhere 

 under stones. It scuttles away out of sight when its hiding- 

 place is disturbed, and is easily recognised by its peculiar 

 mode of progression, for it lies on its side as it propels itself 

 forward. Idotea, a green slater-like isopod, and the sea spider 

 Fycnogonium, are to be seen creeping among sea-weed. The 

 Pycnogonia are phantom crabs which can hardly be said to 

 possess a body at all : these creatures are pretty well made 

 up of legs, the trunk being greatly attenuated. The intestine 

 is prolonged into the limbs ; the eggs are contained in one 

 of the joints of the walking legs of the female, while the male 



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