PTEROPOUA. 425 



rious organs appropriated to different offices, and some of them not 

 a little remarkable from the amazing complication of structure which 

 they exhibit. On each side of the oral opening are three conical 

 appendages (^/zg.198, c, s), that to a superficial examiner might ap- 

 pear to be mere fleshy tentacula, but, in reality, they are instruments 

 of prehension of unparalleled beauty and astonishing construction. 

 Each of these six appendages, when examined attentively, is seen 

 to be of a reddish tint ; and this colour under the microscope is 

 found to be dependent upon the presence of numerous minute 

 isolated red points distributed over its surface. When still fur- 

 ther magnified, these detached points are evidently distinct organs, 

 placed with great regularity so as to give a speckled appearance to 

 the whole of the conical appendage ; and their number at a rough 

 guess may be estimated at about three thousand. Every one of these 

 minute specks is in fact, when more closely examined, a transpa- 

 rent cylinder, resembling the cell of a Polyp, and containing within 

 its cavity about twenty pedunculated discs, which may be protruded 

 from the orifice of their sheath {fig. 199, c), and form so many 

 prehensile suckers adapted to seize and hold minute prey. Thus, 

 therefore, there will be (3000 x 20 x 6) 360,000 of these micro- 

 scopic suckers upon the head of one Clio ; an apparatus for prehen- 

 sion perhaps unparalleled in the creation. 



When not in use, the appendages referred to are withdrawn, and 

 concealed by two hood-like fleshy expansions, which, meeting each 

 other in the mesial line, completely cover and protect the whole of 

 this delicate mechanism, as represented in fig. 198, A. 



Still, however, even when the hoods are drawn over the parts 

 they are intended to defend, the Clio is not left without tactile 

 organs wherewith to examine external objects ; for each valve of the 

 hood is perforated near its centre, and, through the apertures so 

 formed, two slender filiform tentacula {fig- 198, c, &), somewhat 

 resembling the feelers of a snail, are protruded at the will of the 

 animal ; and by means of these it is informed of the presence of food, 

 and instructed when to uncover the elaborately organized suctorial 

 apparatus destined to seize it and convey it into the mouth. 



The mouth itself is described by Cuvier as being a simple trian- 

 gular opening, resembling the wound inflicted by a trocar ; and in 

 the solitary specimen at his disposal he did not succeed in detect- 

 ing any dental structures. Eschricht, however, with superior oppor- 

 tunities, was more successful in displaying the oral organs ; and 

 found the Clio to possess jaws of very singular conformation, and a 



