2 Prof. W. C. M'Intosh on certain 



processes to the zoophyte on whicli it lives, so that it can 

 perch further out in the surrounding water. The nests 

 of the littoral Amj^ihWio'e under stones are other familiar 

 instances. In the group of the Molluscoids the gelatinous 

 " houses " of Apyendicidarians^ which in St. Andrews Bay 

 occasionally so distend the larger nets that they burst, are 

 examples, and tlie "houses" can be cast off and renewed at 

 the pleasure of the owner. The remarkably branched struc- 

 ture formed by Cephalodiscus (one of the discoveries of the 

 ' Challenger ') is another notable instance, for this not only 

 forms a complete protection, but probably mimics the shape 

 of the seaweeds or other structures in its neighbourhood. 

 Amongst the Mollusca the nests of Lima are perhaps the 

 best-known examples, though the homes of others are not 

 devoid of interest. Thus Entoconclia dwells as a parasite — a 

 very rare thing in mollusks — in the interior of >SV/«a/>to, while 

 another {Montacuta substriaia) clings to the spines of the 

 purple heart-urchin. In neither, however, is a distinct 

 " house " formed ; and I may at once explain that by the 

 term " house " or " home " I mean that foreign bodies are 

 employed in addition to the secretion poured out by the 

 animal itself. 



In the present instance, however, we shall confiue our 

 attention to a group of marine animals not yet mentioned, 

 viz., the marine annelids or marine worms [Polijchata)^ a 

 series in which very great variety as well as very great com- 

 plexity of structures for the protection of their soft bodies is 

 exhibited. Moreover, the group is one in which beauty in 

 external coloration is combined with remarkable life-histories 

 and organization. Thus the glassy or golden bristles of some 

 (Euphrosynidce and Aniphiiiomidai) cover the back and sides 

 with a crisp fringe, while the burnished spines and long hairs 

 — constantly glistening with all the hues of a permanent 

 rainbow — of such as the sea-mouse are gorgeous to behold. 

 The pearly lustre of xVe^y7<^/f_y.s, the brilliant tints of yellow, 

 green, blue, red, and purple which characterize the Phvllo- 

 docidte, Alciopithe, llcsionida', and iSereida', the rich brown 

 touches of the KSyllidte, and the deep red of the branchial 

 plumes of the Eunicidre, Terebellida^, Sabellidai, and Serpu- 

 lidie, can only be compared with the most beautiful types of 

 butterflies avid birds. The remarkable power of budding and 

 even branching, the alternatiun of generations, the meta- 

 morphoses during development, the social (eonnnensali.stic) 

 habits, ]»hospliuiescent properties, ])0wers of })erforating rocks, 

 shells, and other substances, the value of almost all as food or 

 as bait for fishes, and some even as nourishment for man, 



