CHAP. III. THE TURBINELLID^E. 7 5 



is even more so. Triton clandestinum has the obsolete 

 plaits and the internal 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 Terebra, 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 TURBINELLIDJE form our next great di- 

 vision of the predatory shell-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 

 Turbinellidce be known by this canal being considerably 

 lengthened.* The animals, unfortunately, of nearly all 

 the typical genera are as yet quite unknown t; 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 Tur- 

 binellidce, 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 MuricidcK. 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. TURBINELLIN^B, 

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

 much lengthened, and the spire generally papillary. 2. 

 SCOLYMIN^J, 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 Cassince, the 

 second the Murlcince of the last family; and both are 



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



f Guilding has ascertained that of Scolymus, and Quoy those of Eburna 

 and Strutheolaria : the former has not a probosciform mouth, but the two 

 latter have this structure highly developed. 



