202 TEREBELLA. 



taculum seizes a fragment to be elevated to the orifice, instead of being 

 abandoned if too ponderous and unwieldy,, two or three others unite 

 their efforts in raising the load to its intended position. An empty 

 mussel shell, above half an inch long, was thus elevated and secured in 

 its place to augment an edifice in progress. 



Great expedition is exhibited in fabricating a tube solely of sand, un- 

 der total deficiency of more favourite materials. Then are heavy loads 

 dragged towards its naked body, with which the mouth is speedily oc- 

 cupied. But shell, as best adapted for the labours of the architect, re- 

 ceives a decided preference. 



Some particles of this substance are certainly swallowed, but from 

 the dimensions of others incorporated with the edifice, they must be 

 combined with adhesive matter for fixture. When recovered from the 

 sea, the whole structure consists of a very tough silk covering with the 

 fragments of shell. 



Perhaps this animal enjoys distinguished reproductive properties. 

 Sundered portions survive a long time, and the lower part of mutilated 

 specimens is completely regenerated, as we have seen in the case of the 

 Terehella tuberculata. 



An immense quantity of spawn was produced by a specimen of the 

 Terebetta conchileqa early in December. It covered the bottom of a nar- 

 row jar, and on gross computation consisted of at least 8000 ova or cap- 

 sules, perhaps imbedded in albuminous matter, invisible from transparence 

 or tenuity. The ovum is very minute, spherical, and reddish, of various 

 intensity, according to the parent. Under the microscope, an internal 

 substance has been discovered within the diaphanous integument, which 

 might be the embryo. Plate XXVIII. fig. 7, ova. 



Thousands of minute carnation ova, discharged by another specimen, 

 perished accidentally in September. 



On one occasion a number of specimens having reached me near the 

 end of December, were found much weakened by the impurity of the 

 water. Some having been extracted from their tubes as they protruded 

 far, one or two produced a multitude of eggs. 



During the earlier days of November, numerous spherules appeared 



