. The biology of spiders. Spiders; Insects. INTERNAL STRUCTURE 47 acid. On dilution with a considerable proportion of water the chitin is reprecipitated. It is a colourless amorphous powder, unaffected by alkalis or by any of the ordinary- organic solvents, and soluble only in concentrated mineral acids. When boiled with strong acids, it is hydrolysed to acetic acid and glycosamine. The formula C15H26N2O10 has been suggested for it, when this action would be : 2C15H26N2O10+2H2O -> 3CH3COOH +4CH2OH() Below the cuticle is a layer of cubical epithelium known as the hypodermis.
. The biology of spiders. Spiders; Insects. INTERNAL STRUCTURE 47 acid. On dilution with a considerable proportion of water the chitin is reprecipitated. It is a colourless amorphous powder, unaffected by alkalis or by any of the ordinary- organic solvents, and soluble only in concentrated mineral acids. When boiled with strong acids, it is hydrolysed to acetic acid and glycosamine. The formula C15H26N2O10 has been suggested for it, when this action would be : 2C15H26N2O10+2H2O -> 3CH3COOH +4CH2OH() Below the cuticle is a layer of cubical epithelium known as the hypodermis. This is in- terrupted only where one of its cells has become modified into a hair-producing cell or trichogen. The body of the trichogen sinks below the hypo- dermal level, through which the shaft of the hair or spine rises, piercing the cuticle which sur- rounds it by a diminutive em- bankment and forming a tricho- pore (Fig. 31). On the inner side the hypo- dermis is lined with pavement epithelium known as basement membrane. Thus cuticle, hypo- dermis, and basement membrane compose together the body-wall. The Endoskeleton But there is also need for internal skeletal structures, chiefly for the attachment of muscles. The most important of these is the endosternite in the cephalothorax, a plate of chitin which it is not very difficult to dissect out, clean, and examine. Its shape is shown in Fig. 32. When in position, the endosternite lies below the stomach and above the ventral nerve ganglia. Many muscles are attached to. Fig. 31.—Section of Seta- producing Cell of Epeira Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Savory, Theodore Horace, 1896-. London : Sidgwick & Jackson
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecti, booksubjectspiders
