{17} 'Familie der Regenwurmer,' p. 13. Dr. Sturtevant states in the 'New York Weekly Tribune' (May 19, 1880) that he kept three worms in a pot, which was allowed to become extremely dry; and these worms were found "all entwined together, forming a round mass and in good condition."{18} 'De Lumbrici terrestris Hist. Nat.' p. 19.
{19} 'Archives de Zoologie experimentale,' tom. vii. 1878, p. 394. When I wrote the above passage, I was not aware that Krukenberg ('Untersuchungen a. d. physiol. Inst. d. Univ. Heidelberg,' Bd. ii. p. 37, 1877) had previously investigated the digestive juice of Lumbricus. He states that it contains a peptic, and diastatic, as well as a tryptic ferment.
{20} On the action of the pancreatic ferment, see 'A Text-Book of Physiology,' by Michael Foster, 2nd edit. pp. 198-203. 1878.
{21} Schmulewitsch, 'Action des Sucs digestifs sur la Cellulose.' Bull. de l'Acad. Imp. de St. Petersbourg, tom. xxv. p. 549. 1879.
{22} Claparede doubts whether saliva is secreted by worms: see 'Zeitschrift fur wissenschaft. Zoologie,' B. xix. 1869, p. 601.
{23} Perrier, 'Archives de Zoolog. exper.' July, 1874, pp. 416, 419.
{24} 'Zeitschrift fur wissenschaft. Zoologie,' B. xix, 1869, pp. 603- 606.
{25} De Vries, 'Landwirth. Jahrbucher,' 1881, p. 77.
{26} M. Foster, 'A Text-Book of Physiology,' 2nd edit. 1878, p. 243.
{27} M. Foster, ut sup. p. 200.
{28} Claparede remarks ('Zeitschrift fur wisseuschaft. Zoolog.' B. 19, 1869, p. 602) that the pharynx appears from its structure to be adapted for suction.
{29} An account of her observations is given in the 'Gardeners' Chronicle,' March 28th, 1868, p. 324.
{30} London's 'Gard. Mag.' xvii. p. 216, as quoted in the 'Catalogue of the British Museum Worms,' 1865, p. 327.
{31} 'Familie der Regenwurmer,' p. 19.
{32} In these narrow triangles the apical angle is 9 degrees 34 seconds, and the basal angles 85 degrees 13 seconds. In the broader triangles the apical angle is 19 degrees 10 seconds and the basal angles 80 degrees 25 seconds.
{33} See his interesting work, 'Souvenirs entomologiques,' 1879, pp. 168-177.
{34} Mobius, 'Die Bewegungen der Thiere,' &c., 1873, p. 111.
{35} 'Annals and Mag. of N. History,' series ii. vol. ix. 1852, p. 333.
{36} 'Archives de Zoolog. exper.' tom. iii. 1874, p. 405.
{37} I state this on the authority of Semper, 'Reisen im Archipel der Philippinen,' Th. ii. 1877, p. 30.
{38} Dr. King gave me some worms collected near Nice, which, as he believes, had constructed these castings. They were sent to M. Perrier, who with great kindness examined and named them for me: they consisted of Perichaeta affinis, a native of Cochin China and of the Philippines; P. Luzonica, a native of Luzon in the Philippines; and P. Houlleti, which lives near Calcutta. M. Perrier informs me that species of Perichaeta have been naturalized in the gardens near Montpellier and in Algiers. Before I had any reason to suspect that the tower-like castings from Nice had been formed by worms not endemic in the country, I was greatly surprised to see how closely they resembled castings sent to me from near Calcutta, where it is known that species of Perichaeta abound.
{39} 'Zeitschrift fur wissenschaft. Zoolog.' B. xxviii. 1877, p. 364.
{40} 'Zeitschrift fur wissenschaft. Zoolog.' B. xxviii. 1877, p. 356.
{41} Perrier, 'Archives de Zoolog. exper.' tom. 3, p. 378, 1874.
{42} This case is given in a postscript to my paper in the 'Transact. Geolog. Soc.' (Vol. v. p. 505), and contains a serious error, as in the account received I mistook the figure 30 for 80. The tenant, moreover, formerly said that he had marled the field thirty years before, but was now positive that this was done in 1809, that is twenty-eight years before the first examination of the field by my friend. The error, as far as the figure 80 is concerned, was corrected in an article by me, in the 'Gardeners' Chronicle,' 1844, p. 218.