tn.p. ex., F.D.). The upper strands of the upper sheet, 

 and the inner strands of the lower sheet, after a superficial 

 course run together, and sinking- deeper join in with the 

 great lateral muscle. 



Muscles attaching gills to mantle. — The narrow 

 muscular band which runs along the external surface of 

 the efferent vessel of the gill, from the lip downwards, 

 after leaving this artery at the base of the gill, runs 

 obliquely inwards over the ventral surface of the kidney 

 to meet its fellow in the middle line (PI. V, fig. •'!?, 

 Br.M.). The common strand now runs posteriorly, over 

 the ventral surface of the g'enital capsule, and is inserted 

 on the inner face of the mantle, just posterior to the 

 vertical septum. Possibly this strand affords additional 

 support to the genital gland, when it is enlarged at the 

 time of sexual activity, as well as serving to deflect the 

 gill- 



Funnel. 



This may well be studied along with the mantle 

 cavity, as it is closely related thereto. It is a hollow 

 conical structure, truncated anteriorly (PI. II, fig. 8, F.), 

 which is attached to the ventral surface of the head, and 

 is free laterally and ventrally, and for about the anterior 

 third of its dorsal wall (fig. 11, F.). The anterior and 

 external opening of the funnel is about 13 mm. in 

 diameter, in a large specimen, while the posterior internal 

 opening is very much larger and forms the base of the 

 cone. At the posterior end, the ventral edge of the 

 funnel is recurved, ventrally and anteriorly. This forms 

 a ridge, which is more pronounced at the sides than in the 

 centre, and forms part of the funnel articulation (PL II, 

 fig. da, l.f.r.). The weak locking apparatus is in strong 

 contrast with the firm one found in Si />///, Loligo and 



