Throughout: Lymph nodes tend to cluster next to blood vessels that feed all the abdominal organs. There are hundreds of lymph nodes within the abdominal cavity, the retroperitoneum (the area by the spine behind the intestines), the pelvis, and the groin. In fact, there all lymph nodes throughout the body (except the brain and eye). ...Read more.
The various fish groups account for more than half of vertebrate species. There are almost 28,000 known extant species, of which almost 27,000 are bony fish, with 970 sharks, rays, and chimeras and about 108 hagfish and lampreys.
Types Of Shellfish. Shellfish include a broad range of animals, from abalone to octopus, but they arenât all as different as you might think. Edible shellfish are divided into two main categories: crustaceans, which include crabs and shrimp, and mollusks, which include subgroups called bivalves, gastropods and cephalopods.