Ii6 Glimpses of Marine Life on the Forth. [Sess. 



On a neighbouring rock we come upon specimens of the 

 pretty little sea -slug {Doris). Most gasteropods have their 

 respiratory organs protected by a shell, but in the nudibranchs 

 they are exposed. The gills of Doris are in the form of a 

 feathery rosette placed far back on its dorsal surface; it 

 has two short feelers in front; the skin is rough and tuber- 

 culated; white or light-brown marked with a darker shade, 

 the coloration of Doris reminds one of that of the fallow deer. 

 Some of the deep-water nudibranchs are arrayed in the love- 

 liest crimson tints imaginable. Not far from the spot where the 

 Doris specimens were obtained, there were seen hanging from 

 the sides of the rock several pieces of what looked like damp 

 cloth. One could fancy it was washing-day, and that some 

 liliputian laundress of the deep had hung out her clothes to 

 dry. Examination revealed a corded tissue not very unlike 

 linen, the transverse threads being rows of eggs. This form 

 is taken by the spawn of sea-snails : the specimens found were 

 in fact the nidamental ribbons of Doris. 



A small mollusc common in the same locality is the Chiton 

 or mail-shell. Its body is of a flattened oval shape, and is 

 covered by a shell composed of several pieces jointed together 

 like ancient armour. The clusters of small, yellow, pitcher- 

 shaped bodies, seen adhering to many of the rocks about, are 

 the eggs of Purpura, one of our commonest shells. The eggs 

 are out of all proportion to the parent mollusc, and must have 

 grown since they were deposited. 



The rocks in many places are incrusted with pink coral- 

 lines : these stony sea -weeds resemble stalagmite, and it is 

 hard to convince oneself that they are vegetable productions 

 at all. Corallines petrify as they grow, a tendency unfortu- 

 nately not confined to marine algse : living fossils, it is alleged,, 

 are to be found even in the human species itself. 



11. 



The bread - crumb sponge occurs sparingly on our coast. 

 White, with a closer texture than the sponges of commerce, 

 this is one of the siliceous sponges, the horny skeleton being 

 strengthened by needle-shaped spicules of flint. A sponge 



