Squid breathe by drawing water through their siphons into their mantles, the large muscular coverings over their bodies, where it passes over their two sets of gill filaments, absorbing oxygen and releasing carbon dioxid... More »

In the hydra, respiration is accomplished via diffusion of molecules of oxygen and carbon dioxide through the skin. The hydra's simple cellular structure ensures that its body's skin layers are thin enough for diffusion ... More »

The five main groups of vertebrates, known as classes, are: fish, amphibians, reptiles, birds and mammals. Vertebrate species are assigned groups based on shared traits, such as body covering, the ability to maintain a s... More »

Squid extract oxygen from the water using gills, just as fish do. These gills are located in the squid's mantle, the soft but muscular cavity behind the squid's head. More »

Squid usually have two tentacles and eight arms that are also called legs. A giant squid's tentacles can be up to 10 meters long and the arms up to 3 meters long. The smallest squid is only 2.5 centimeters in length tota... More »

Squid do not have any legs at all, but they do have eight arms and two tentacles, making for a total limb count of 10. All cephalopods have at least eight limbs, but only squid and cuttlefish have true tentacles. More »

www.reference.com Pets & Animals Marine Life Squid

Squid engage in internal fertilization, but rather than using a penis for the transference of sperm cells, the males place a packet of sperm cells, called a spermatophore, into the female’s mantle, or body cavity; howe... More »