. The Australian zoologist. Zoology; Zoology; Zoology. 308 THE LORICATE* OF THE NEOZELANIC REGION, beak. The line of demarcation between each lateral and central area is called the diagonal. As a rule the anterior valve forms a complete area aa regards sculp- ture, which generally resembles that of the lateral areas of the median valves; occasionally the apex is differentiated. The posterior valve is divided into two areas by a mucro or projection, more or less central. The area in front of the mucro is styled the antemucronal, and the area behind is styled the post- mueronal area; the former
. The Australian zoologist. Zoology; Zoology; Zoology. 308 THE LORICATE* OF THE NEOZELANIC REGION, beak. The line of demarcation between each lateral and central area is called the diagonal. As a rule the anterior valve forms a complete area aa regards sculp- ture, which generally resembles that of the lateral areas of the median valves; occasionally the apex is differentiated. The posterior valve is divided into two areas by a mucro or projection, more or less central. The area in front of the mucro is styled the antemucronal, and the area behind is styled the post- mueronal area; the former is sculptured similarly to the central areas of the median valves, and the latter is sculptured similarly to the anterior valve. In some genera the mucro is so far behind the centre that the post-mueronal area is reduced to an inconspicuous tract, or is altogether absent. The articulamentum is larger than the tegmentum, projecting in front, as regards valves 2 to 8, in two sutural laminae, which are separated by a bay called the sinus. At the sides of the median valves and round the edge of the end valves, most Loricates have projecting insertion plates, to which the girdle is attached. These insertion plates are generally cut into by slits. From the slits to the apex of each valve run more or less distinct slit-rays. The edges of the insertion plates between the slits are called teeth, which are in some genera finely cut into combs or pectinated; in some thickened outside or propped, and in some cut quite Fig. 3.—Composite diagram of a Loricate, showing the parts of the shell (A. to H.); the variations of sculpture more frequently oc- curring (I. to N.), and the prin- cipal varieties of girdle-covering (0. to S.). A.—Anterior valve, B.—Median valves, C.—Posterior valve, D.— Lateral area, E. Central area, F.— Mucro, G-—Ante-mucronal area, H.—Post-mueronal area. I.—Radially ribbed, J.—Divari- cating radially, K.—Nodulose, L. —Radially nodulose, M
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1914
