Homes or Tabes formed hij Annelids, 15 



is neatly titlf<l. Hutli saiul-^'iaiii.s and ciMucnt have a dull 

 ofhreuus \\\\k-~ and tliL' |iaU'a' are likewise dull browui.sli. 

 The second form [Ci.stenides hiiperhorea) lia.s a large ta[)erin!i^ 

 tube, al.so sliglitly curved, cuniposeil, a.s a rule, in the hirge 

 examples ot" moderate grains ot" sand in the midst of much 

 cement, so that the surface varies in ciiaracter from the fore- 

 going, though it is also ochreous. Moreover, the smaller 

 diverge so considerably trum the larger grains that the 

 ))attcrn is less unif(^>rni. Both tubes are strong and resistant, 

 better able to coj)e with their rougher surroundings than those 

 of Liujis uv Anijihictene ; and both are more opaque. The 

 inner surface of these tubes is smoother than the outer, and 

 in C. Iiyperborea the lining of cement is sometimes very con- 

 spicuous. 



Amongst tliose which fashion translucent homes from the 

 body-secretion alone, the most remarkable type is lIijaluKjeciaj 

 which, both in our owu and in foreign seas, constructs a tube 

 ranging in size from a crow- to a goose-quill, and in the large 

 foreign examples gently tapered from one end to the other. 

 The tube is so Hrni and yet so elastic that, like a goose-quill, 

 it can be cut into the sha[)e of a pen, a feature almost vvitli- 

 out ])arallel in other than the group of birds. The great 

 length and perfect smoothness of this tube are characteristic. 

 The inhabitant belongs to the same family as Northiuy and 

 is allied to the Eunicids with their fine red brauchiie and 

 iridescent bodies, and, like them, has a well-armed proboscis. 

 The Eunicidi\3, however, secrete parchment-like tubes more 

 or less opaque, and, as a rule, they are protected by immer- 

 sion in sponges or placed under shells and other structures, 

 whereas the tubes of Ui/alincecia stand freely in the mud. 



Spiochwtopterui>, again, secretes a translucent flexible tube 

 of great length, and often with a series of collars or frills, and 

 an allied form, PhyUocha'topteruSj procured by tiie ' Chal- 

 lenger,' shows similar rings in its semiopaline tube, which 

 also has a very neat diaphragm with a central aperture pos- 

 teriorly. Moreover, many of the tubes are forked, an appear- 

 ance due to fracture and the secretion of a new piece with 

 which the tunnel is continuous, while the old fractured end 

 has its tube closed and remains as a useless process. As a 

 general rule ordinary chemicals have little eliect on these 

 hyaline tubes. 



On the other hand, Mfjxicola surrounds itself with a trans- 

 lucent gelatinous investment of considerable thickness, from 

 the midst of which it stretches its beautifully formed and 

 gaily tinted branchial fan. 



In none of the foregoing instances does the architect of the 



