the Buccal Parts of the Mollusca. 79 



Fig. \c. Pneumodermon, with everted prehensile hooks (harpagae). (Figs.l, 

 1 b, and 1 c from 'Voyage de la Bonite.') 



Fig. 1 d. One of the sacs opened, to show the evertile hooks, with some 

 detached corneous spines. (From Van Beneden's ' Exercices 

 zootomiques.') 



Fig. 2. Clione limacina, Phips. : the anterior part of the oesophagus. 

 The harpaga of the right cheek-pouch is everted; the left re- 

 tracted, and seen through an opening. 



Fig. 2 a. The harpaga, with from 24 to 32 corneous hooks. From Esch- 

 richt's ' Undersogelse om Clione borealis.' 



Fig. 3. Onychoteuthis, from the ventral side, with protruded arms. It is 

 douhtful whether the metacarpal suckers are really destined 

 to act against each other, as represented by Ferussac and D'Or- 

 bigny. 



Fig. 4. Conus tulipa : the oral veil expanded at the edge, and opened to 

 show the haustellum. 



Fig. 4 a. The oral veil in a contracted state. 



Fig. 4 b. The intestinal channel and its glands, the two liver-lobes, and an 

 intermediate small so-called "gland," perhaps the true stomach. 

 Over the nervous ring is the " organe en pioche," attached to 

 the oesophagus by muscular bands; but I have not been able, in 

 a specimen of C. consors, to discover any communication with the 

 interior of the oesophagus. It cannot, therefore, represent the 

 papillae of the tongue, which in Littorina and Patella are of enor- 

 mous length. At the insertion of the " organe en pioche," close 

 to the base, is the long vermiform canal 'of the single " glande 

 salivaire cucumiforme." The walls of this cylindrical organ are 

 enormously thick and muscular; and it therefore seems tome 

 not to be a salivary gland, but a suctorial stomach, like that of 

 most haustellate insects. A similar unequal sac, in the same 

 position, is found in the following Mollusca, all of which are 

 provided with an haustellum : — 



Murex cichoreus, Voyage de l'Astrolabe, t. 36. f. 1, et Suppl. 

 t. 2. f. 1 d, troisieme glande salivaire. 



Dolium olearium, ibid. t. 41. f. 4. 



Valuta fusus, Q. & G. ibid. t. 44. f. 9 h, " diverticulum ou caecum 

 cesophagieu tres-eonside'rable ;" and f. 10 and 11. 



Ancillaria albisulcata, ibid. t. 49. f. 11 d, "diverticulum, 

 espece de caecum." 



The petiolate cheek-pouch in Lamellidoris, described by Mr. 

 Hancock, is perhaps, too, a kind of instrument destined to produce 

 a vacuum, like the suckers of Cephalopoda. 



Fig. 4 c. The " organe en pioche" opened, to show the arrows turning the 



points in a different direction in each branch. 

 Fig. 4 d. Different forms of the arrows, hollow inside. 



(Figs. 4-4 d from 'Voyage de l'Astrolabe,' t. 44.) 

 Fig. 5. Pharynx of Pleurobranchus, showing the "lames laterales" t\a 



both sides of the tongue, a. The hard parts of the " lames 



laterales," strongly magnified. (From Lacaze-Duthier's 'Anato- 



mie du Pleurobranche orange,' /. c.) 



