. La biologia di ragni. Ragni; gli insetti. Alcuni altri ARACHNIDA o accostate tra di loro. Questi sono usati in scavando. L'ultima coppia di appendici su prosoma sono i chilaria. Il coxal giunti di pedipalpi e le gambe sono diretti verso l'interno processi coperta con spine e arredate con denti di frantumazione. Essi assistono in masticating il cibo prima che entri nella bocca. L'appendice del primo segmento addominale è la mediana opercolo genitale, attraverso cui la femmina deposita le uova. I prossimi cinque segmenti portano abbinato gill-libri (Fig. 109). Questi organi respiratori sono ve
1496 x 1670 px | 25,3 x 28,3 cm | 10 x 11,1 inches | 150dpi
Altre informazioni:
Questa foto è un'immagine di pubblico dominio, il che significa che il copyright è scaduto o che il titolare del copyright ha rinunciato a tale diritto. Alamy addebita un costo per l'accesso alla copia ad alta risoluzione dell'immagine.
Questa immagine potrebbe avere delle imperfezioni perché è storica o di reportage.
. The biology of spiders. Spiders; Insects. SOME OTHER ARACHNIDA or brought close together. These are used in burrowing. The last pair of appendages on the prosoma are the chilaria. The coxal joints of the pedipalpi and of all the legs have inwardly directed processes covered with spines and furnished with crushing teeth. They assist in masticating the food before it enters the mouth. The appendage of the first abdominal segment is the median genital operculum, through which the female deposits the eggs. The next five segments carry paired gill-books (Fig. 109). These respiratory organs are very different from anything possessed by the land Arachnida. The gill-book itself is borne on the hind surface of the expodite or outer branch of the appendage. It consists of a hundred and fifty to two hundred leaves within each of which the blood is flowing, while the oxygen- ated water circulates be- tween the leaves. In this possession of breathing organs visible from outside the body, Limulus resembles the extinct Eurypterida. The king-crab spends the greater part of its life burrowing in the sand under shallow water. It is probable that in this comparatively unpopulated environment it enjoys a freedom from competition with the more active creatures, and that this has enabled it to persist in its relatively primi- tive form since the Silurian era. It makes its way through the mud with astonishing facility. Bending its body upwards, it urges the front edge of its carapace downwards and forwards, while the sharply-pointed spine is pressed into the mud behind. At the same time, the extensible fan-like organs which terminate the fourth pair of legs are thrust backwards, so that the lobes are opened by the. Fig. 109. crab. -Gill-book of the King- Partly after Shipley.. 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
