WOODWARD : ANATOMY OF PTEEOCEEA. 147 



right splanchnic ganglion. A pair of otocysts are closely applied to 

 the pedal ganglia, differing from those of Strombus in being situated 

 behind instead of anterior to the pedal ganglia. 



The Crystalline Style in its most typical condition is a firm, 

 gelatinous, transparent rod, situated in a caecal diverticulum of the 

 stomach, into the cavity of which it projects freely. The style is 

 generally regarded as being peculiar to the Lamellibranchiata, and 

 amongst them to be restricted to the Dimyarian forms. This, how- 

 ever, is not the case, as was shown as long ago as 1829 by Collier,^ 

 who wrote as follows : " There is an organ, the crystalline stiletto, 

 confined erroneously by a celebrated naturalist to bivalves, which is 

 found in every species of Strombus, in Trochus tiirritus, and a species 

 (vertayus) of Murex.''^ He further gives a detailed description of the 

 position and character of this structure. These observations were 

 subsequently confirmed by Huxley in PteroceraP" 



In 1855 Moquiu-Tandon^ described in Bythinia a long cartilaginous 

 rod, which he considered the analogue of the crystalline style of the 

 Lamellibranchiata. Fischer* speaks of a fi'ee chitinous (?) lamella 

 shaped like the screw-propeller of a boat in the stomach of Cyclostoma 

 (evidently the " fleche tricuspide "), and states that a stylet analogous 

 to this is found in Paludina (? the same as in Bythinia), Trochus, and 

 Strombus, but he evidently does not regard it as having any relation to 

 the crystalline style of the Lamellibranchs. We also find its presence 

 described by Yon Jhering* in Lythoylyphus. Haller® has described the 

 presence in Strombus and in Rostellaria of a long tapering caecal 

 outgrowth from the pyloric end of the stomach ; this is obviously 

 the homologue of the crystalline style sac of Pterocera, He does 

 not, however, describe any solid style as being found within this 

 cfecum, nor does he make any reference to Collier's or Huxley's 

 description of Pterocera, or compare this caecum with that of the 

 Lamellibranchs. He figures a slight csecal outgrowth in Dolium 

 galea, and in speaking of the caecum of Haliotis (see also Lang') 

 suggests that it is concerned in storing up and absorbing the fluid 

 food. Yung^ describes in Helix pomatia a outicular lining to the 

 intestine, which he compares with the crystalline style of Lamelli- 

 branchs. Kieferstein ^ also describes a small pyloric caecum in Murex 

 and Buccinum. 



We see from the above that the presence of a crystalline style in 

 the Gastropoda, and its connection with the stomach or intestine 

 {i.e. midgut), either in a distinct caecum (Strombidae) or free in the 



1 Ediub. New Phill. Journ. vol. vii. 1829, pp. 230-231. 



2 Huxley, Phil. Trans. 1853, p. 60. 



3 Moquin-Tandon, Moll. Terr, at Fhiv. France, 1855, tome i. p. 44. 

 * Fischer, Manuel d. Conchyliologie, p. 41. 



6 Von Jherin>,^ Mai. Blatter (2), viii. p. 98. 

 « Haller, Morph. Jahr. Bd. xix. 1893, pp. 582-584. 

 ' Lang, Lehrb. Vergl. Anat. p. 774. 



^ Yuug, Mem. Cour. Acad. Belg. 4to. t. xlix. No. 1, p. 34. 

 ^ Bronn's Klassen u. Ordmmg. d. Thier.-Keichs. Bd. iii. Abth. 2, Malacozoa, 

 1862-66. 



