. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. CONTRIBUTIONS TO THE KNOWLEDGE OF MARINE MOLLUSCA 153 thereafter loosely and irregularly coiled, dextral, widening rapidly from 2nd (or 3rd) whorl. Aperture circular. Slit on first 3 postnatal whorls closed, there- after more or less moniliform. Growth-lines strong, sinuous, fissured on the larger whorls appearing as if slashed with a knife (cf. Morch, i860, p. 401). Diam. aperture 4-5 mm. Operculum plug-like, outer surface with 6 or 7 septa radiating from the centre, representing successive gro
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. CONTRIBUTIONS TO THE KNOWLEDGE OF MARINE MOLLUSCA 153 thereafter loosely and irregularly coiled, dextral, widening rapidly from 2nd (or 3rd) whorl. Aperture circular. Slit on first 3 postnatal whorls closed, there- after more or less moniliform. Growth-lines strong, sinuous, fissured on the larger whorls appearing as if slashed with a knife (cf. Morch, i860, p. 401). Diam. aperture 4-5 mm. Operculum plug-like, outer surface with 6 or 7 septa radiating from the centre, representing successive growth accretions, the scarious margin des- cending spirally (4-5 whorls) to the basal (last formed) layer. Thiele described and figured the edges as fringed (setose), but in the present specimens they are. Fig. 30. a, tubes of Vermetus periscopium n. sp. b, portion of tube of Tenagodus wilmanae (Tomlin). c, two views of protoconch of T. chuni Thiele. d, early whorls of T. chuni Thiele. merely scarious, and on the earlier whorls somewhat frayed. The nucleus and initial whorls seem to be gradually worn away. Diam. of specimen here figured 4 mm. Creamy-white, protoconch pale brown, operculum dark brown. Radual with c. 35 rows, weak and feebly 'chitinised', central and lateral plates with entire cutting-edges, both marginal plates simple, without denticles. 340 51' S., 190 37' E. 80 metres; 340 8' S., 240 59' E. 80 metres; 350 16' S., 22° 26' E. 155 metres; 350 29' S., 210 3' E. 102 metres (Thiele). Off East London and Cape Morgan, 22-85 fathoms; off Umvoti River (Natal) 23 fathoms; off Tugela River (Natal) 47 fathoms; in sponges (S. Afr. Mus. coll.). Remarks. The initial whorls do not always stand up so prominently as in the example figured, but may be quite depressed into the succeeding whorl. Sometimes the tube forms a very open spiral. Only one animal, containing embryos, and two opercula, were obtained from the material (East London). In both opercula the marginal fringes
Size: 2243px × 1114px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
