CIRRHOPODA. 357 



drag tli em down into the vicinity of the mouth, where, being 

 seized by the jaws, they are crushed and prepared for digestion. 

 No sense but that of touch is required for the success of this 

 singular mode of fishing ; and the delicacy with which the tentacula 

 perceive the slightest contact of a foreign body, shows that they 

 are eminently sensible to tactile impressions. As regards the 

 digestive organs, we have already described the prominent mouth 

 (Jig- 169, b) 9 with its horny palpiferous lip and three pairs of 

 lateral jaws. The oesophagus (Jig. 169, c) is short, and firm in 

 its texture ; it receives the excretory ducts of two salivary glands 

 of considerable size (fig- 168, d, d), and soon terminates in a 

 capacious stomachal receptacle, the walls of which are deeply 

 sacculated and surrounded by a mass of glandular caeca (Jig. 169, d) 

 that represent the liver, and pour their secretion through numerous 

 wide apertures into the cavity of the stomach itself. The intes- 

 tine (e,/) is a simple tube, and runs along the dorsal aspect of 

 the animal, wide at its commencement, but gradually tapering 

 towards its anal extremity ; it terminates at the root of the tubular 

 prolongation (k) by a narrow orifice, into which a small bristle (g) 

 has been inserted. 



(394.) Little is satisfactorily known relative to the arrangement 

 of the blood-vessels and course of the circulation in these animals. 

 Poli imagined that he had discovered a contractile dorsal vessel, 

 intimating that he had perceived its pulsations in the vicinity of 

 the anal extremity of the body ; and, although his observations upon 

 this subject have not been confirmed by subsequent investigations, 

 analogy would lead us to anticipate the existence of the heart in 

 the position indicated by the indefatigable Neapolitan zootomist. 

 The lateral appendages (Jig. 167, d, d, d) are most probably 

 proper branchial organs, but, perhaps, not exclusively the instru- 

 ments of respiration ; since the numerous cirrhi no doubt co-ope- 

 rate in exposing the blood to the action of the surrounding 

 medium, a function to which they are well-adapted by their struc- 

 ture and incessant movements; especially, as each cirrhus is seen 

 under the microscope to be traversed throughout its whole length 

 by two large vascular trunks, one apparently arterial, and the other 

 of a venous character. 



(395.) With respect to the organization of the reproductive sys- 

 tem in these creatures, the most discordant opinions are expressed 

 by different writers ; no two authors agreeing either concerning the 

 names or offices which ought to be assigned to different parts of 



