NOTES. 4 1 3 



CoMtis fossilis, which is specially adapted to animal feeding, frequently 

 eats species of Lemna. Many caterpillars, among the Noctuidse— for 

 instance, species of Agrotu — eat each other if they are shut up together 

 in a box, though in freedom they feed only on roots and leaves. The 

 larvEE of the common frog eat plants, the full-grown frogs only insects, 

 worms, or even amphibia. All apes, although their teeth are apparently 

 adapted to a fruit or vegetable diet, are passionately fond of animal 

 food, as birds, eggs, insects, Sec. ; they will even gnaw bones. Many 

 parrots eat butter, bacon, lard, snails, raw eggs, beetles, the brains of 

 small birds, and marrow. Most Nematoda live as parasites in animals, 

 but a few live in plants — Tylenchns tritici, for instance, which lives in 

 the flower of wheat, and Tijlenchus dijjsaei. 



Most Holothurise shovel sea-sand into their mouths with their 

 tentacles, and leave it to the intestine to select the organic particles 

 of nutriment that are mixed with it. Thyonidinm molle, on the Peruvian 

 coast, feeds, on the contrary, on sea-weeds. Almost all Hymenoptera 

 are phytophagous, excepting only a few wasps and hornets, and ants 

 which feed on dead flesh. Certain snakes — Leptognathiis and Amlly- 

 eej>7ialns (see Giinther, Ann. Mag, N. Hist. 1872, ix. 29) — feed on snails, 

 while all other species eat vertebrata or sometimes minute insects. 

 Cyclura loplioura, a species of iguana-like lizard in Jamaica, is herbi- 

 vorous, although it belongs to a carnivorous group. Most tortoises live 

 on animals ; only a few land tortoises eat vegetables. All birds of prey 

 feed on mammals, birds, or reptiles ; but the secretary-bird, that stalks 

 about on long stilt-like legs like a heron, rummages about in the mud, 

 like a duck, for aquatic creatures of all kinds. One of the most interest- 

 ing examples is afforded by the genus Onchidium among the pulmonate 

 moUusca. The lingual tongue of those moUusca which live exclusively 

 on animal food is very sharply distinguished from that of the herbi- 

 vorous species ; a few of these last, as Lymnrea stagnalis, are, no doubt, 

 carnivorous also (see p. 59 of the text) ; but in general we may consider 

 ourselves justifled in determining those molluscs as herbivorous of 

 which the rachis has the same structure as those of Helia; or Lymncea. 

 AH the species of Onchidium which I have hitherto been able to examine, 

 about four-and-twenty, have exquisite herbivorous teeth, and, neverthe- 

 less, do not use them for eating ofE plants, but exclusively for shovelling 

 in sea-sand or mud. Hence we see that even the organs of mastication, 

 which yet must be quite specially adapted to the nutriment obtainable 

 at the time and to the mode of obtaining it, may under some circum- 

 stances be used in very various ways ; and we must therefore conclude 

 that in comparing living creatures with fossil ones these organs can 

 afford no absolutely reliable means for determining the food and mode 

 of life of these primeval creatures. These exceptions, moreover, afford 

 us a further example of the proposition stated in the text, that even 

 organs which appear to us to be adapted to a special office are never- 



