APHEODITA. 167 



the light, chiefly quitting its haunts cautiously and timidly at night, as 

 if dreading enemies, or in quest of prey. 



However, it is scarcely ever observed to feed ; nor, amidst great 

 variety of substances offered, is almost any thing found acceptable. A 

 vessel containing a specimen, eight weeks in my possession, being re- 

 plenished with sea-water, a portion of mussel was dropped before the 

 Aphrodita next morning. Darting out the proboscis it sucked up the 

 mussel. Eight or ten days afterwards the like occurred, the proboscis 

 having been quickly withdrawn on both occasions. 



The same specimen survived some time longer, and then perished 

 from impurity of the water. This is the most common of the genus. 



PLATE XXIV. 



FIG. 3. Aphrodita squamata, large specimen, one pair of scales, and the ter- 

 minal caudal bristles defective. 



4. Perfect specimen from Shetland, with twelve pair of scales. 



5. Head of a perfect specimen, with two pair of scales adjoining, slightly 



enlarged, 



6. Anterior extremity of fig. 4, upper surface, enlarged. 



7. Posterior extremity of the same, under surface, enlarged. 



8. Ordinary specimen, wanting one or two pair of scales. 



9. Ova, enlarged. 



10. Proboscis, enlarged. 



' 3. APHRODITA VARIANS. Plate XXIV. Figs, yd, 11, I > 



The variable aspect of this animal is extremely embarrassing to the 

 general observer. It is sufficient to excite his doubts whether he sees 

 before him a distinct species, or whether only successive varieties. I have 

 been hitherto unable to detect such uniform and permanent features as 

 to pronounce all the specimens, not few in number, as identified by for- 

 mation with each other. Externally they are certainly very unlike, but 

 it may be only in accidental characters. 



