314 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



After ascertaining the position of affairs, the worm 

 turned its tube over so that the flat stone should overhang, 

 and then proceeded to protect the mouth by secreting a 

 short terminal portion between the walls, attaching thereto 

 a flat shell of smaller size than usual. It thus avoided 

 increasing the length of the tube. It will be noticed that 

 in this instance the small shell was actually found and 

 affixed in the way supposed in the suggested building 

 process. 



In captivity these worms appear to be less hardy than 

 TlyaUnoecia. 



What their natural enemies may be I do not know, but 

 while in my aquarium I lost one specimen, devoured by a 

 small Grephyreau worm Thalassema neptuni, which tore 

 away the back end of the Onvphis tube, entered and 

 remained therein twenty-five days, having barricaded the 

 front end of the tube by drawing in a large grain of sand. 



I have thus far dealt only with the habits and defensive 

 mechanism of the British species of the family, but 

 perhaps the most interesting example of these protective 

 valves is afforded by the tube of Nothria pyenobranchiata, 

 for the privilege of dissecting and examining which I 

 am indebted to Prof. F. Jeffrey Bell, of the British 

 Museum (Natural History) at South Kensington. 



The specimen, which had been obtained by (he 

 "Challenger" Expedition off the Chilian Coast, from a 

 depth of 2,225 fathoms, was a fragment about 4| inches 

 iong, evidently one end onty of a tube. It consisted of 

 a tough membranous inner sheath, coated outside with fine 

 mud, and strengthened on the upper side, with the tests of 

 foraminifera and other matter. It was elliptical in 

 section, and 7-lGths of an inch across in its widest part. 



On splitting open the extremity by cutting in the direc- 

 tion of its shortest axis, two pairs of very perfect internal 



