50 HALF-AN-HOUR AT 



this tree, as has been noticed in some other cases by Professor 

 GulHver. 



It is important to remember that the two divisions of nature — 

 the animal and the vegetable — form parts of one continuous 

 whole, and that a good acquaintance with plant organisation is 

 essential to the study of the problems involved in animal life. 



Red Earth-Mite (PI. IV., Figs. 1—9). — I have a slide of this, 

 purchased under the name Trovibidium holosericeiim, and have not 

 yet examined further to see if this name be correct. " The species 

 are numerous and not well characterised." (" Micro. Diet.," sub. 

 Trombidium.) It is very common in my garden in summer, and 

 seeing this slide makes me ashamed not to know more about it. 

 The antennse-like organs are called " palpi" ; their structure is 

 peculiar, the penultimate joint having the form of a powerful 

 claw, which denotes raptorial habits ; the last joint is pyriform and 

 fleshy. " The cheliceres (mandibles of some authors) are cultrate" 

 (Siebold and Stannius, Vol. I., p. 376). Look what formidable 

 weapons they are ! Like a Malay " crease," that of the left side 

 has the blade broad, and its edge jagged with saw-teeth ; its 

 companion is narrower, more pointed, and apparently nearly 

 smooth on the edge. There is a labium, plumose at the 

 extremity. The hairs to which the velvety appearance is due are 

 of two well-marked types — the one like tiny feathers, the other 

 like little clubs. The clubbed hairs occur on the hinder part of 

 the upper abdominal surface as six radiating bands. They clothe 

 the whole of the under surface. They are seated on transparent 

 cylindrical papillae, and by looking for some of the latter, where 

 a sectional view is presented, are seen to have a dozen short hairs 

 radiating from their bases. The cutting away (as it might be 

 termed) of the ends of the limbs to accommodate the claws 

 strikes me as a highly curious mechanical arrangement ; its 

 purpose being to prevent the sharp tips needed for seizing and 

 holding their prey from being worn. I have not specially looked, 

 but have little doubt they walk, as it were, on the heel and wrist 

 joints. A similar arrangement is met with in Ticks. Flies when 

 walking over rough surfaces, where their pads are not required, 

 draw them back, and then, like most beetles in similar circum- 

 stances, hold by the claws alone. 



Skin of Small Spotted Dog-Fish, Scyllium Caniculum (PI 



III., Figs. 7 — 11). — This, in addition to its exquisite beauty, is a 

 most instructive specimen. Have you read and pondered " Huxley 

 on the Study of Natural History," a lecture on Zoology, delivered 

 at the South Kensington Museum in i860, reported in Scic?ice Gossip 

 for April, 1867, p. 73 ? If not, I would like you to do so before 

 reading another word of these remarks, or you cannot properly 



