34 VIGNETTES FROM INVISIBLE LIFE. 



their dwellings together, and so offers greater resist- 

 ance to any sharp-eyed and rapacious strangers of 

 which there are many who may be disposed to 

 gobble them up. The former is the " family," the 

 latter the "social" life. 



Closely allied to Limnias are (Ecistes, Ceplia- 

 hmpJio/i, and others all tube dwellers and bearing 

 a strong family likeness to each other. The differ- 

 ence between Lintmas and (Eciste* consists princi- 

 pally in the character of the rotary organ, which 

 in the former is ^/-lobed, and single in the latter; 

 while in Cephalosiphon there is an additional 

 attraction in a curious syphon-like projection, 

 the use of which seems to correspond to the 

 antenna? of insects as a projecting feeler after 

 information for the benefit of its proprietor. 



There is yet another tube-dweller which must 

 not escape our notice. It is described in the 

 "II. M. &. Journal" for December, 1878, as a 

 new form, and obtained the name (Ecistes iimbellu, 

 from the peculiar umbrella-like form and structure 

 of its circular disc or head. There are the ribs and 

 covering, and when fully expanded or partially 

 folded up, the resemblance, as far as the upper 



