. The Australian zoologist. Zoology; Zoology; Zoology. 188 A MONOGRAPH OP THE AUSTRALIAN LORICATES, the basis of specific variation. The median valves are divided into two lateral and two central areas, connected by a dorsal area, extending- along- the ridge of the valve, the posterior extremity of which, if projecting, is called the 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 as regards sculpture, which generally resembles that of the lateral areas of the median valves; occasionally the apex is
. The Australian zoologist. Zoology; Zoology; Zoology. 188 A MONOGRAPH OP THE AUSTRALIAN LORICATES, the basis of specific variation. The median valves are divided into two lateral and two central areas, connected by a dorsal area, extending- along- the ridge of the valve, the posterior extremity of which, if projecting, is called the 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 as regards sculpture, which generally resembles that of the lateral areas of the median valves; occasionally the apex is differentiated. The posterior valve is divided into two by a mucro or projection, more or less central. The area in front is styled the unlc- mucronal, and the area behind is styled the post-mucronal 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-mucronal area is reduced to an inconspicuous tract, or is altogether Fig 2. Anterior, median, and posterior valves of a Loricate, show- ing external features. T. Tegmentum, tt. Teath of in- sertion plate. S., Sinus. Sutural laminae. Fig. 3. —Anterior, median and posterior valves of a Loricate, show- ing interior features. A. Articulamentum. tt. Teeth. Ap. Apex. S. Slit. B. Beak (or I'mboi. C. Callus. The articulamentum is larger than the tegmentum, projecting m 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 outer edge of the end valves, most Loricates have projecting insertion plates, to which the girdle is at- tached. These insertion plates are generally cut into by slits. From the slits to the apex of each valve inside ran slit-rays. The edges of the insertion plates be- tween the slits are called teeth, which are in some genera finely cut into
Size: 1921px × 1301px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1914
