NKWTON : CONCHOI.OGICAI, FKATURES OF I.ENHAM SANDSTONES. 



149 



(/7Ctni/!t//t,CKRVtUiUM 62 



tricinctus, Murkx 70 



tricincttis, 



Ptychopotamides 70 

 Trigoneu.a ... 104 

 tn'gomila, Nucui.A 81 



Tritia 74 



Triton ... 63, 65, 74 



Trivia 69 



TROCHID.E ... 67 

 Trochocyathus? 58 

 trochoidea, EuMAR- 



GAKITA ... 67 



trochoidea, Margarita 



62, 67 

 Trochus... 63, 68, 72 



Trophon 



75 



Trophonopsis ... 



76 



tnmida, Cyprina 



101 



Turbo 



71, 72 



tiDrictila, MUREX 



n 



TURRID^E 



n 



ttirrijera, Pi.EURO- 





TOMA 



62, 77 



ttirrifera, TURRIS 



77 



/•age 



77 

 72 



97 

 69 

 69 



TURRIS 



TURRITELLID/E 

 undnlata, OsTREA 

 tnigarica. Patella 

 ungaricns, Capulus 

 ungulatus, Mytii.us 

 Upper Crag 

 Van den Broeck,j£^ Broeck 

 variabilis, Terebra- 



TUI.A 110 



varians, NaTICA 62, 70 

 variiis, Pecten ... 

 Vasseiir, G. 

 Vexericardia ... 

 VENERID/E ... 

 7'ent>i(osa. Arcopagia 



102 

 venlriiosa, CORBIS I02 

 ventricosa, Ringicula 



62, 79 

 ventriiosa, Thracia 



63, 109, no 

 Venus ... loi, 102, 105 

 Vienna Basin ... 65 



Vigo Hill ... 59 



61 



63 

 "3 



99 

 105 



Volsella 



VOI.UTA ... 



VOLUTID^^: 

 Waenrode beds . 

 Wallas, Graham 



paoe 

 84 



76, 79 

 76 



64,65 

 57 



Waterschoot sea Gracht 65 

 Whitaker, W. ... 61 

 Winterswyk ... 66 

 Wood, Searles ... 59 

 woodwardi, ECHINUS 58 

 Woolwich and Read- 

 ing beds ... 61 

 Xenophora 



xenophorid.e: 



Yoldia 



Zanclean ... 



Zaria 



Zimniermann, X. G. 

 zizyphinum, Calli- 



ostoma 

 zizypkinus, Trochus 



63 



Zone of Area diliivii 



63, 72 

 72 

 82 



114 

 72 



114 



68 

 64 



The " Nerita jaculator " of O. F. Miiller and Paludestrina. — Some speci- 

 mens of Palndeslrina jcnkinsi, collected in Hertfordshire, in a pond near Elstree, 

 in September, 1915, gave a good demonstration of their method of extruding the 

 young, while under observation in a dish. The snail being in the customary crawl- 

 ing position, the shell is suddenly jerked upwards and forwards (i.e., as if the 

 animal were beginning to withdraw) at intervals of perhaps a quarter or half a 

 minute, three or four times in succession. At each jerk a small white body is shot 

 out into the water with a vigour sufficient to carry it half an inch or so horizont- 

 ally. On examination these white bodies proved to be young ones. This "specta- 

 culum mirum et jucundum " was apparently seen by O. F. Miiller or> i6th July, 

 1769 ( Vermiiim Historia, vol. ii. (1774), p. 186) ; he gives a lively account of the 

 expulsion of the small white bodies, and his subsequent failure to recover them for 

 microscopic examination, and is so indignant that a snail of such remarkable 

 powers should be named after the tentacles which any common mollusc has, that 

 he deliberately renames it "juculator." It is true that I noticed nothing like the 

 resolution of the l)odies into anything which was suggestive of the tiny worms he 

 mentions, and Miiller may have been observing something quite different, but the 

 general similarity nl any rate suggests that he may have included Paludestrina 

 with Bithinia.^h, E, Boycott {Read before the Society, Nov. 8th, 1916). 



