1927] «4 Pilsbry-Bequaert, The Aquatic Mollusks of the Belgian Congo 241 
Vayssiére,! who has published the best account we have of Trun- 
catella, considered its respiration branchial. Though not living in the 
water, he believes that the moist station and occasional splashing of the 
waves supply sufficient water. He mentions keeping specimens alive 
for ten days in the moist air of a closed glass. We believe that, though 
provided with a gill, Truncatella respires free air as a rule. The senior. 
author has collected living specimens in situations reached by the waves 
only at intervals of months. He has published drawings of specimens of 
I’. bilabiata* which had lived in a loosely plugged vial without water for 
about six weeks. These snails promptly became active on dropping a 
slip of moistened blotting paper into their vial, and lived for several 
weeks longer. : 
Fig. 39. Teeth of Truncatella caribxensis Reeve. 
TRUNCATELLA Risso . 
Truncatella Risso, 1826, ‘Hist. Nat. Europ. Mérid.,’ IV, p. 124. Type: Trun- 
catella levigata Risso = Helix subcylindrica Linné. 
The following species have been recorded from the Ethiopian Region: 
Truncatella pellucida Dourn, 1860, Malakoz. Blatter, VI, p. 203. Red Sea. 
Truncatella princeps Dourn, 1866, Malakoz. Blatter, XIII, p. 134. Prince’s 
Island. 
Truncatella semicostulata JIcKELI, 1874, Nova Acta Ac. Nat. Cur. Dresden, 
XX XVII, 1, p. 189, Pl. vu, fig. 8.. Dahlak Island, off the coast of Eritrea. 
Truncatella teres PFEIFFER, 1856, Proc. Zool. Soc. London, p. 336; 1856, ’Monogr. 
Auricul. Viv.,’ p. 188. Originally described from Mauritius and Australia, this 
species has also been recorded from the Red Sea and from Port Elizabeth, Cape 
Colony. 
Synceridze 
(ASSIMINEIDZ of authors) 
Shell ovate-conic, compact, the whorls flattened. Peristome simple, the margins 
connected by a closely adnate callus. Operculum corneous, paucispiral, with excentric 
nucleus. : 
Pe hyl., XXXITI, p. 253. 
mmr eit Fg Proc. Ac rae Sci. aeons aes LXVI, p. 426, Pl. x1v (illustrating 
locomotion). 
