186 SOLENOCONCHIA. 



of which, in the estimation of a conchologist, surpasses 

 that of the still sought-for discovery of the sources of the 

 Nile. His " Histoire de F Organisation et du Developpe- 

 ment du Dentale " appeared in the ' Annales des Sciences 

 Naturelles ' for 1856 and 1857, and is worthy of his 

 academical fame. His researches were prosecuted at 

 St. Malo ; D. Tarentinum was the subject. He killed 

 and prepared the animals for anatomical dissection, 

 either with prussic acid, or by drowning them in sea- 

 water, particularly in that which contained the putrid 

 corpses of their late companions. In the delightful 

 ' Sea-side Studies ' of Gr. H. Lewes will be found a 

 thoughtful discussion of the very difficult question 

 whether the simpler animals feel pain. He answers it 

 in the negative; and I agree with him to a certain 

 extent. A predaceous beetle with a pin through it will 

 eat up other insects confined in the same collecting-box ; 

 and every part of a polype cut in pieces will nourish. 

 At all events the Invertebrata appear to be exempt from 

 that sense of apprehension, or anticipation, which we 

 regard as the worst pain. The Dentalium burrows in 

 sand by means of its conical foot in a slanting direction ; 

 the narrow end is of course uppermost, and is kept in 

 communication with the water or air for the purpose of 

 respiration. It feeds on Foraminifera and other minute 

 organisms, which it catches with its thread-like tentacles. 

 These are of all lengths and sizes, and are insinuated 

 among the grains of sand on every side; they are 

 covered with cilia, especially at the points, which resem- 

 ble suckers. They are thrown off by the Dentalium 

 under certain conditions, and may occasionally be seen 

 detached and wriggling like taper hair-worms. Tere- 

 bella and other tubular annelids have similar organs. 

 Being highly contractile, these tentacles convey the food 



