470 THE SECRETARY OS ADDITIONS TO THE MEXAGERIE. [Nov. 19, 



EXPLANATION OF THE PLATES. 

 Plate XXV. 



Fig. 1. The mantle-cavity of Neothauma seen from front and showing contents. 



The ridge marked B.r, is very strongly developed and functions as a 



protection to the gill during the partial occlusion of the gill-chamber 



during the development of the relatively enormous young. Compare 



Plate XXVI. fig. 3. 

 Fig. 2. The buckle-mass and salivary glands of Neothauma. x4. 

 Fig. 3. Dissection of the mantle of Vivipara vivipara female, made to show the 



presence of the less-developed ridge R.r., homologous with that of 



Neothauma. x2. 

 Fig. 4. The nervous system of Neothauma dissected from above and showing the 



zygoneurous connection between the pleural ganglion and the sum' t- 



intestinal ganglion on the left. x4. 

 Fig. 5. Dissection of the nervous system of Vivipara vivipara, showing the 



normal dyaloneurous condition of the nerves on both sides, xti. 



Plate XXVI. 



Fig. 1. Lateral view of the nervous system of Neothauma, showing the' zygo- 

 neurous connection and the generally detatched condition of all the 

 ganglia, viewed from the left. 



Fig. 2. Living specimen of Kytra kirki, dredged in Tanganyika, at Masswa, in 

 twenty-five fathoms of water. 



Fig. 3. Partially dissected female Neothauma, showing young being developed 

 mi situ. 



Figs. 4, 5, & 6. Three marked varieties of the shell Neothauma, which are found— - 

 (4) at the south, (5) in the middle, and (6) at the north end of Tan- 

 ganyika. Natural size. 



Reference letters to figures in the Plates. 

 A. Anus. R. Renal aperture 



B.e. Buckle-commissure. 

 27.WI. Buckle-mass. 



C.g. Cerebral ganglion. 



L.c. Labial commissure. 



O.t. Otocyst. 



O.s. Osphradium. 

 Tl.ij. Pleural ganglion. 



R.r. Respiratory ridge. 



S.i.g. Supra-inte.stinal ganglioi 



T. Tentacle. 



V.g. Visceral ganglion. 



Y. Young of Neothauma. 



Z. Zvgoneural commissure. 



November 19, 1901. 



William Bateson, Esq., M.A., F.B.S., Vice-President, 

 in the Chair. 



The Secretary read the following reports on the additions made 

 to the Society's Menagerie during the months of June, July, 

 August, September, and October, 1901 : — 



The number of registered additions to the Society's Menagerie 

 during the month of June was 418, oE M'hich 85 were by presen- 

 tation, 86 by birth, 11 by purchase, and 236 were received on 

 deposit. The number of departures during the same period, by 

 death and removals, was 172. 



The number of registered additions to the Society's Menagerie 



