CHAP. III. THE TURBlNELLIDiE. 75 



is even more so. Triton ckmdestinum has the obsolete 

 plaits and the mternal channel of Tritonidea ; while its 

 thickened outer lip and more produced channel is suffi- 

 cient to give it a place within the limits of Triton. The 

 circle of the MuricidcB is thus complete ; but whether 

 Leiodomus is a sub-genus of Terebi-a, or really that type 

 which passes into Microtoma, is a matter of doubt ; its 

 analogy, however, to Harpa, as shown in the animal, is 

 a weighty consideration, although we have no interme- 

 diate links by which it is connected to Trochia. 



(66.) The TuBBiNELLiDiE form our next great di- 

 vision of the predatory sheU-fish. As the Muricidce 

 are chiefly distinguished by the general shortness of the 

 testaceous canal which receives the respiratory siphon, or 

 by its total absence; so may the great majority of the 

 TurhinellidcB be known by this canal being considerably 

 lengthened.* The animals, unfortunately, of nearly all 

 the typical genera are as yet quite unknown f; so that 

 we have only a few detached land-marks, as it were, to 

 assist us in the arrangement of their shells. Looking, 

 therefore, to such characters, we observe that the Tiir- 

 hinellida, as a whole, are remarkable for the length of 

 the basal canal ; and that the two typical sub-families 

 have the pillar plaited, — a character never met with in 

 the Muricidce. The volutes, indeed, possess it ; but the 

 total absence of a canal in those shells serves at once to 

 distinguish them. We shall now arrange the whole 

 under the following families: — 1. TuRBiNELLiNiB, 

 having a large, very heavy, and smooth shell, the canal 

 nmch lengthened, and the spire generally papillary. 2. 

 ScoLYMiNiE, equally strong and ponderous with the last, 

 but the shell is rough, with foliated spines or tubercles, 

 as in Murex, and the canal short. These two are the 

 typical groups ; the first representing the Cassintr, the 

 second the Muricince of the last family ; and both are 



* Except in the Eburnidce, and some of the aberrant ScohjmincE. 



t Guilding has ascertained that oi Scolymus, and Quoy those oi Eburna 

 and Strutheolaria : the former has not a probosci^brm mouth, but the two 

 latter have this structure highly developed. 



