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The male accessory glands are the ampullary gland, seminal vesicle, prostate, bulbourethral gland, and urethral gland. [5]The products of these glands serve to nourish and activate the spermatozoa, to clear the urethral tract prior to ejaculation, serve as the vehicle of transport of the spermatozoa in the female tract, and to plug the female tract after placement of spermatozoa to help ensure ...
[45] [46] [47] [38] In many cases, there is clear evidence that the initial concretion formed around some kind of organic nucleus. [48] The origin of the carbonate-rich septaria is still debated. One possibility is that dehydration hardens the outer shell of the concretion while causing the interior matrix to shrink until it cracks.
Being hindgut fermenters, these animals ferment cellulose in an enlarged cecum. In smaller hindgut fermenters of the order Lagomorpha (rabbits, hares, and pikas), and Caviomorph rodents ( Guinea pigs , capybaras , etc.), material from the cecum is formed into cecotropes , passed through the large intestine, expelled and subsequently reingested ...
When animal or plant matter is buried during sedimentation, the constituent organic molecules (lipids, proteins, carbohydrates and lignin-humic compounds) break down due to the increase in temperature and pressure.
For most organisms, the resting period is a stage of preparation during which the secretion of fluid from the moulting glands of the epidermal layer and the loosening of the underpart of the cuticle occurs. Once the old cuticle has separated from the epidermis, a digesting fluid is secreted into the space between them.
Hemolymph, or haemolymph, is a fluid, analogous to the blood in vertebrates, that circulates in the interior of the arthropod (invertebrate) body, remaining in direct contact with the animal's tissues. It is composed of a fluid plasma in which hemolymph cells called hemocytes are suspended. In addition to hemocytes, the plasma also contains ...
Tissue derived from mesoderm partly lines the fluid filled body cavity of these animals. Thus, although organs are held in place loosely, they are not as well organized as in a coelomate. All pseudocoelomates are protostomes; however, not all protostomes are pseudocoelomates. An example of a pseudocoelomate is the roundworm.
Unlike Benton, for example, Jacques Gauthier and colleagues forwarded a definition of Amniota in 1988 as "the most recent common ancestor of extant mammals and reptiles, and all its descendants". [26] As Gauthier makes use of a crown group definition, Amniota has a slightly different content than the biological amniotes as defined by an ...