Owen's description showed this view to be groundless, and he attributed the extraordinary development of the toucan's beak to the need of compensating, by the additional power of mastication thus given, for the absence of any of the grinding structures that are so characteristic of the intestinal tract of vegetable-eating birds - its digestive organs possessing a general simplicity of formation.
The xylem and phloem are nearly always found in close association in strands of various shapes in all the three main organs of the sporophyteroot, stem and leafand form a connected tissue-system running through the whole body.
True hypertrophy is commonly found in the hollow muscular organs such as the heart, bladder and alimentary canal.
The genital organs in both Asteroidea and Echinoidea would retain the interradial position they first assumed in Edrioaster; and in Echinoidea their primitive temporary openings to the exterior were converted into definite pores, correlated with five interradially placed plates at the aboral pole.
Diseases and distrubances of the ordinary functions of the organs were attributed to the influence of planets or explained as due to conditions observed in a constellation or in the position of a star; and an interesting survival of this bond between astrology and medicine is to be seen in the use up to the present time of the sign of Jupiter 4., which still heads medicinal prescriptions, while, on the other hand, the influence of planetary lore appears in the assignment of the days of the week to the planets, beginning with Sunday, assigned to the sun, and ending with Saturday, the day of Saturn.
Whether in the Metanemertines, where the blood fluid is often provided with haemoglobiniferous disks, the chief functions of the side organs may not rather be a sensory one needs further investigation.
Lastly, the philosophers of the second physical succession - Empedocles, Anaxagoras, Leucippus - not directly attacking the great mystery of the One and the Many, but in virtue of a scientific instinct approaching it through the investigation of phenomena, were brought by their study of sensation to perceive and to proclaim the inadequacy of the organs of sense.
The exit of these organs takes many shapes, of value in systematic work.
In the more primitive types of flowers the torus is more or less convex, and the series of organs follow in regular succession, culminating in the carpels, in the formation of which the growth of the axis is closed (fig.
The crinoid type was differentiated by the extension of the food-grooves and associated organs along radial outgrowths from the theca itself.