812 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



the tube is lengthened the uppermost position is assumed 

 by the opposite sides alternately. 



Like Hyalinoecia, Onuphis conchilega travels about the 

 sea-bottom in a caterpillar-like fashion. Should its tube 

 be overcast (as shown by fig. G), it speedily rights it again. 

 On such occasions ihe worm protrudes from the front end 

 of iis tube \ to J of an inch of the fore part of its body, 

 bending it sideways over one edge of the shell which ought 

 to be overhanging (a, fig. G), and then, by a sudden 

 muscular twist of the body, the tube is turned over into its 

 proper position. I have witnessed this many times ! 

 Under the shelter of the overhanging front (a, fig. 5) the 

 worm is safe in exploring the immediate neighbourhood 

 in search for food, and also for material suitable for 

 extending its dwelling. AVhen one of these beautiful flat 

 tubes was first placed in my hands by Professor Herdinan, 

 I was quite at a loss to imagine a method by w T hich the 

 worm could construct it : but with the knowledge since 

 gained of the peculiar habits of this species, and aided 

 by information gained by using the transparent-tubed 

 Hyalinoecia as a key to those of the famil}- generally, the 

 difficulty has disappeared. 



The post-larval stage, and very young specimens of this 

 worm, have unfortunately hitherto escaped us, conse- 

 quently my theory requires confirmation,; but, guided by 

 analogy, it seems most probable the formation of the tube 

 is much as follows : — A membranous tube will first be 

 secreted by the young worm. In this it will settle down 

 (like Terebella and Pectinaria) to the sea-bottom, upon 

 which it will creep, like Hi/alinoceia. until it meets with 

 a minute, fiat fragment of shell, or other material suitable 

 for attachment to the under side of its tube. This, properly 

 secured by secretion or action of the head parts (a point which 

 I am still investigating). will form the first overhanging shield. 



