Murdoch. — Oft the Anatomy of Paryphanta fumosa. 157 



appear to form regular rows, except some two or three on 

 the neck. Behind the visceral mass there is a median dorsal 

 line which does not extend to the fitll length of the tail, 

 and the rugiE on this area are considerably smaller than on 

 the anterior portion of the animal. The tentacles are com- 

 pletely retracted, and the labial projections, if any, are not 

 distinguishable. On the external surface of the mantle, and 

 close to its margin, is a lightly impressed line of a dark-blue 

 colour, and on the under-side are small right and left lappets, 

 the latter forming a narrow inconspicuous fold. The foot is 

 of a sepia colour around the margins, shading to lighter in the 

 middle area ; except in colour there is no indication of it being 

 divided into median and lateral areas. It is thrown into 

 several transverse prominent folds, and its w^hole area has the 

 appearance of being minutely transversely and longitudinally 

 grooved. This rugose aspect is doubtless largely due to its 

 contracted condition. 



The buccal mass (fig. 3) is large, and very similar to the 

 corresponding organ in other members of the genus ; but in 

 the form of attachment of the retractor muscle it differs from 

 any that have come under my notice. The muscle is com- 

 pletely attached to the posterio-ventral side of the buccal 

 mass ; it extends from the posterior and forward to the flexure, 

 as shown in the figure. The muscle forms, as it were, a 

 double cushion (fig. 4), attached on the inner margins and 

 anterior areas. In P. hochstetteri, Pfr., and P. busbyi, Gray, 

 the retractor muscle almost envelops the curved-down pos- 

 terior end of the buccal mass. It is roughly in the form of a 

 hollow cone, but the greater portion of the muscle certainly 

 goes to the ventral side. In longitudinal section of the buccal 

 mass it is found that the area of greatest muscular concentra- 

 tion is at tlie ventral flexure or immediately posterior to it. 

 To this area are attached the enormously developed posterio- 

 dorsal series of muscles, which proceed from the odontophoral 

 cartilage and radular sac. It would thus appear that in 

 fnmosa the retractor muscle is more completely applied to the 

 area where the greatest resistance is required. 



The radula has the formula 38-0-38, the rows of teeth 

 forming an obtuse angle curved towards the margins. The 

 teeth (tig. 5) are all aculeate. They increase in length to about 

 the ninth ; a few succeeding teeth are apparently without 

 change, thence they very gradually decrease in length ; the 

 twenty-fifth to the twenty-seventh diminish somewhat more 

 rapidly, and the last is reduced to about one-half of the length 

 of the adjoining tooth. With the exception of the innermost 

 tooth, all have practically the same diameter ; thus the teeth 

 towards the margins, and the centre also, are in proportion to 

 their length more robust than the intermediate teeth. 



