We might not inappropriately call this type of structure pseud-axial. It simulates that of the higher plants in certain superficial characters. We see in it a primary axis along which development may continue indefinitely, and from which there bud out, laterally, secondary axes of like nature, bearing like tertiary axes; and this is a mode of growth with which Phænogams make us familiar. § 185. Some of the larger _Algæ_ supply examples of an integration still more advanced; not simply inasmuch as they unite much greater numbers of morphological units into continuous masses, but also inasmuch as they combine the pseudo-foliar structure with the pseud-axial structure. Our own shores furnish an instance of this in the common _Laminaria_; and certain gigantic _Laminariaceæ_ of the Antarctic seas, furnish yet better instances. In _Necrocystis_ the germ develops a very long slender stem, which eventually expands into a large bladder-like or cylindrical air-vessel; and the surface of this bears numerous leaf-shaped expansions. Another kind, _Lessonia fuscescens_, Fig. 37, shows us a massive stem growing up through water many feet deep--a stem which, bifurcating as it approaches the surface, flattens out the ends of its subdivisions into fronds like ribands. These, however, are not true foliar appendages, since they are merely expanded continuations of the stem. In _Egregia_ branches of the thallus not only take the form of leaves, but these are differentiated into several categories in accordance with a division of labour. In any of these _Laminariaceæ_ the whole plant, great as may be its size, and made up though it seems to be of many groups of morphological units, united into a compound group by their marked subordination to a connecting mass, is nevertheless a single thallus, which is added to by intercalary growth at the “transition place,” at the junction of the stem-like and leaf-like portions. The aggregate is still an aggregate of the second order. [Illustration: Fig. 37.] [Illustration: Figs. 38–40.]