. Bulletin of the Natural History Museum Zoology. FOREGUT ANATOMY AND CLASSIFICATION OF CONOIDEA 135 Raclula The radula has been by far the most studied of the organs of the foregut and there are many published illustrations of conoidean radular teeth ( Powell, 1966; McLean, 1971; James, 1980; Bandel, 1984; Bogdanov, 1990; Nybakken, 1990 and Taylor, 1990). Shimek & Kohn (1981) classified turrid radulae into a number of functional groups and attempted a cladistic analysis of radular characters. However, amongst the 'lower' turrids there is little evidence from direct observations to sup
. Bulletin of the Natural History Museum Zoology. FOREGUT ANATOMY AND CLASSIFICATION OF CONOIDEA 135 Raclula The radula has been by far the most studied of the organs of the foregut and there are many published illustrations of conoidean radular teeth ( Powell, 1966; McLean, 1971; James, 1980; Bandel, 1984; Bogdanov, 1990; Nybakken, 1990 and Taylor, 1990). Shimek & Kohn (1981) classified turrid radulae into a number of functional groups and attempted a cladistic analysis of radular characters. However, amongst the 'lower' turrids there is little evidence from direct observations to support their functional categories. Indeed, recent evi- dence shows that even in the least-derived radulae which possess a strong radular ribbon, the marginal teeth can be held singly at the proboscis tip in a stabbing position (Kantor & Taylor, 1991). A radula is present in most Turridae, all Conidae, possibly all Pervicaciidae and some Terebridae. It is absent in some species of Daphnellinae, Taraninae and many species of Terebridae (Miller, 1970; Taylor, 1990). The phenomenon of radula-loss in conoideans has recently been reviewed by Kantor & Sysoev (1989). For the purposes of the present analysis, we have attempted to recognise different morphological types of radula, without any functional interpretation. The radula of the Drilliinae, which is usually regarded as the least-derived condition within the Turridae, has five teeth in each transverse row (Fig. 16a). These teeth are usually refered to as central, lateral and marginal teeth respectively; although there are different interpretations (Kantor, 1990; Starobogatov, 1990). We consider the morphology of each of these teeth in turn. 1. Central tooth A central tooth is present in species of Drilliinae, Pseudome- latominae, Turrinae, Clavatulinae, and Cochlespirinae. It can be reduced and lost in some species of these subfamilies except Pseudomelatominae. (i) In the Pseudomelatominae, the central tooth is fairly robus
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