DESCRIPTIONS OF PREPARATIONS. 



The blood si Helix contains haemocyanin, a respiratory substance in which 

 copper is present in combination with a proteid. It is colourless when deoxidised, 

 bright blue when oxidised. Hence the coelomic fluid of a Helix exposed to air- 

 assumes a violet tinge. The blood-plasma of the pulmonate Planorbis contains 

 haemoglobin. Haematin is found in the liver-secretion of Helix pomatia, H. 

 aspersa, Arion ater, and Limax. Amoeboid corpuscles occur, but rather sparingly, 

 in the blood. 



The shape of the nephridium varies in Pulmonata. It has a long tubular duct 

 in Helix, &c., opening near the anus ; whilst in other Pulmonata, such as Arion, it 

 has a simple round opening. Its cavity is large, and its walls are lamellate. It 

 really consists of a urinary chamber into which open acini of very large calibre. 

 These acini are bound together externally by connective tissue. The renal cells 

 are ciliated, and urates of Ammonium and Calcium are found in them and in the 

 cavity of the sac. Free uric acid and Guanin occur in Zonites as well as Ammonium 

 urate. The nephridium of Helix pomatia is supplied with arterial blood from the 

 pulmonary chamber and by the renal arteries ; by the latter alone in Zonites. 



Gastropoda. Ray Lankester, ' Mollusca,' Encyclopaedia Britannica (ed. ix.), 

 xvi. 1883. Keferstein, Bronn's Klass. und Ordnungen des Thierreichs, iii. 2. 

 1862-66. (Pulmonata, p. 1160.) 



Pulmonata. Semper, Z. W. Z. viii. 1856-57. Leidy, in Binney's Terrestrial 

 Air-breathing Mollusca of the United States, i. 1851, p. 198. For the Slugs, see 

 literature to Plate v (post). 



Helix pomatia. Cuvier, Memoires pour servir a 1'histoire, &c. des Mollusques, 

 1871. (Annales du Muse'um, vii. 1806.) H. aspersa. Howes, Atlas of practical 

 Elementary Biology, 1885, Pis. xiii. xiv. Taylor, Journal of Conchology, iv. 1883, 

 pp. 102-105. Zonites algirus. Nalepa,- SB. Akad. Wien. Ixxxvii. Abth. i. 1883. 

 Ancylus. Sharp, Proc. Acad. Nat. Sc. Philadelphia, 1883. Onchidium (Marine 

 Slug). Bergh, Challenger Reports, x. 1884, p. 126, and M. J. x. 1885. 



Muscles and locomotion of snails. Simroth, Z. W. Z. xxx. Suppl. 1878; xxxii. 

 1879 > xxxvi. 1882. 



Glands of foot. Houssay, A. Z. Expt. (2) ii. 1884. Carriere, A. M. A. xxi. 

 1882. Supra-pedal gland. Sochaczewer, Z. W. Z. xxxv. 1881. Id. and Simroth, 

 ibid, xxxvi. 1882. Sarasin, Arb. Zool. Zoot. Inst. Wurzburg, vi. 1883. 



Mucous threads spun by Mollusca. Martens, Z. A. i. 1878. Eimer, ibid. Tye, 

 Quarterly Journal of Conchology, 1878. 



Pulmonary chamber = a uropneustic apparatus. Von Ihering, Z. W. Z. xli. 1884 ; 

 criticisms of view, see Semper, Arb. Zool. Zoot. Inst. Wurzburg, iii. 1876-77; cf. 

 Simroth, Z. W. Z. xxvi. 1876, p. 337 et seq. 



On Ampullaria. Jourdain, C. R. 88, 1879. Sabatier, ibid, and A. N. H. (5), 

 iv. 1879. 



Vascular system and pulmonary vessels. Nalepa, op. cit. supra. Apertures of 

 capillaries in Arion ater (= rufus]. Jourdain, C. R. 88, 1879. Haemocyanin, 

 properties and distribution. Halliburton, Blood of Decapoda (Crustacea], Journal of 

 Physiology, vi. 1885. MacMunn, Q. J. M. xxv. 1885. Haemoglobin in Mollusca. 

 Ray Lankester, P. R. S. xxi. 1872; cf. Sorby, Q. J. M. xvi. 1876. For colouring 

 matters in general, see Krukenberg, Vergleich. Physiol. Vortrage, iii. 1 884. MacMunn, 

 Proc. Birmingham Philosoph. Soc. iii. 1881-83. Cf. Moseley, Q. J. M. xvii. 1877. 



