470 THE SECRETARY ON ADDITIONS TO THE MENAGERIE, [NoV. 19, 



EXPLANATION OF THE PLATES. 

 Plate XXV. 



Fig. 1. The mantle-cavity of ]>!eothai(,ina seen from front and showing contents. 

 The ridge marked li.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 Vivlpara vivipara female, made to show tlie 

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

 Neothauma. X 2. 



Fig. 4. The nervous system oi NcotJiauma ([issectcA from above and showing the 

 zygoneurous connection between the pleural ganglion and the supra- 

 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. x6. 



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 kir/ci, dredged in Tanganyika, at Masswa, in 

 twenty-five fathoms of water. 



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

 in 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. 



Eeference letters to figures in the Plates. 



A. Anus. 



B.C. Buckle-commissure. 

 B.m. Buckle-mass. 



e.g. Cei-ebral ganglion. 



L.c. Labial commissure. 



O.t. Otocyst. 



O.s. Osphradium. 

 Pl.g. Pleural ganglion. 



E. Penal aperture. 

 B.r. Respiratory ridge. 

 S.i.q. Supra-intestinal ganglion. 

 T. Tentacle. 

 V.g. Visceral ganglion. 

 1'. Young of Neothauma. 

 Z. Zygoneural commissure. 



November 19, 1901. 



"William Bateson, Esq., M.A., P.E.S., Vice-President, 

 in the Otiair. 



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, of which 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 



