PHYLUM MOLLUSCA 



265 



extended, seize the victim with their suckers, and draw it back 

 to the arms, which hold it firmly to the mouth. The funnel (j) 

 is a muscular tube extending out be- 

 yond the edge of the mantle collar (2, g) 

 beneath the head (4). Water is ex- 

 pelled from the o 

 mantle cavity (Fig. 

 192, M.C) through 

 it. The funnel is 

 the principal steer- 

 ing organ; if it is 

 directed forward, 

 the jet of water 

 passed through it 

 propels the animal 

 backward ; if di- 

 rected backward, 

 the animal is pro- 

 pelled forward. 



A thick muscular 

 mantle encloses the 

 visceral mass and 

 mantle cavity. It 

 terminates ven- 

 trally in a collar 

 (Fig. 191, 2, g) 

 which articulates 

 with the visceral 

 mass and funnel 

 by three pairs of 

 interlocking sur- 

 faces. Water is drawn into the mantle cavity at the edge of 

 I the collar by the expansion of the mantle and forced out through 

 the funnel by the contraction of the mantle. On each side of 

 jthe animal is a triangular fin-like projection of the mantle 



Fig. 



192. 



Fig. 191. — The squid, 

 Loligo pealii, side view. 

 A, anterior; D, dorsal; 

 P, posterior; V, ventral. 

 1, fin; 2, edge of mantle; 

 3, siphon ; 4, head ; 

 5, arm; 6, long arm with 

 suckers; 7, arm; 8, eye; 

 q, edge of mantle. (From 

 Williams.) 



Diagram 

 showing the structure of 

 the squid, Loligo pealii. 

 A 1 , arm; A*, long arm 

 with suckers; An, anus; 

 Ca, caecum ; E, eye ; 

 Gi, gill ; Go, gonad ; 

 IS, ink-sac; LV, liver; 

 M.C, mantle cavity; 

 Ne, nephridium; Ph, phar- 

 ynx; Pn, pen; Si, siphon; 

 St, stomach; SiV, valve 

 of siphon. (From Wil- 

 liams.) 



