166 DR. p. L. SCLA'lEB ON THE [Mar. 4, 



Plate XV. 



Fig. 5. The sac fully developed around the larva, which is cut through ventral 

 sucker, s.v., rudimentary seminal vesicle at base of penis ; cm., circular 

 musculature ; l.m., longitudinal musculature ; ski\, ventral sucker. Other 

 letters as in previous figures. X 130. 



Fig. 6. The Cercaria as it occurs in Mytilus. From a specimen stained in toto. 

 cu., cuticle ; m., mouth ; a.s., anterior sucker ; p.s., posterior sucker ; ph., 

 pharynx; s.^^f/., salivary glands ; ce., oesophagus ; diff., digestive caeca; ex., 

 excretory system ; ex.p., pore of same; pe., penis; te., testes; v.d., vasa. 

 deferentia. X 130. 



Fig. 7. The same, in longitudinal section, pa., parenchyma ; pa.n., nucleated sub- 

 cutaneous layer of same; int.ep., intestinal epithelium, in surface view ; 

 g.p., genital pore ; cm., circular musculature ; l.m., longitudinal ditto . 

 m.f., muscle-fibre in pai'onchyma ; n.c, supra-oesophageal nerve-commissure 

 Other letters as in fig. 6. X 130. 



PlATB XVI. 



Fig. 8. Dead Cercaria in Mytilus, with three centres of calcification. X 130. 



Fig. 9. Section of the muscular mantle-margin of Tapes, showing the Sporocysts 

 with contained Cercarise. m., musculature of Tapes ; sp., sporocyst ; 

 cer., Cercaria ; ex., excretory tubes ; dig., digestive cajca ; pe., penis ; 

 s., ventral sucker of same. 



Fig. 10. Pressure preparation of the Cercaria from Sporocyst in Tapes. The speci- 

 men was examined alive, so sexual organs are not visible, e., eyes ; t.p., 

 tactile papillaj ; cZi^f., digestive caeca; ej;., excretory system. X 700. 



Fig. 11. The adult worm from CEdemia nigra L., River Villaine. s.v., seminal 

 vesicle; ov., ovary; ut., uterus; g.p., genital pore. Other letters as in 

 fig. 6. Stained in toto. 



Plate XVII. 



Fig. 12. Mytilus edulis L., Piel, Lancashire. Photo of a thin slice or "SchlifF" 



through centre of pearl, showing calcified Trematode as nucleus. X 25. 

 Fig. 13. Ditto. Pearl formed in sac vacated bj- Trematode. A few granules of 



residual matter have calcified to form nucleus. X 25. 

 Fig. 14. Ditto, showing several centres of calcification in the Trematode. X 25. 

 Fig. 15. Ditto, double pearl, one of constituents being formed around Trematode, 



the other as in fig. 13. X 25. 

 Fig. 16. Pearl from Margaritifera margaritifera Linn., New Guinea, showing 



imperfectly calcified Trematode, witli radially arranged prisms. X 25. 



2. List o£ the Parrots represented in the Society's Collection 

 in January 1902, with Remarks on some of the Rarer 

 Species. By P. L. Sclatek, D.Sc, F.R.S., Secretary 

 to the Society. 



[Received February 20, 1902.] 

 (Plates XYIII. & XIX/) 



The birds in the Society's Parrot-house having been lately 

 re-arranged and the duplicates and " deposited " specimens having 

 been moved to another place, I have thought it worth while to 

 prepare a list of the species of Psittacidte now represented in the 

 Collection, which may be useful in future years, and to add to it 

 a few notes on some of the rarer forms. 



It may be observed that the 147 specimens of Parrots now 



1 For explanation of the Plates, see p. 171. 



