Not only is the coelom thus subdivided, but the enteron (gut, alimentary canal, digestive tube) itself shows indications of three main subsections in continuity with one another: - (I) proboscis-gut (Eicheldarm, stomochord, vide infra); (2) collar-gut (buccal cavity, throat); (3) truncal gut extending from the collar to the vent.
For building and miscellaneous purposes, in addition to the rare woods above named, there are cedars (used in great quantities for cigar boxes); the pine, found only in the W., where it gives its name to the Isle of Pines and the province of Pinar del Rio; various palms; oaks of varying hardness and colour, &c. The number of alimentary plants is extremely great.
The size of the animals varies greatly, from forms a few millimetres in length to Gigantorhynchus gigas, which measures from 10 to 65 cms. The adults live in great numbers in the alimentary canal of some vertebrate, usually fish, the larvae are as a rule encysted in the body cavity of some invertebrate, most often an insect or crustacean, more rarely a small fish.
There are no alimentary canal or specialized organs for circulation or for respiration.
The embryo thus passes from the body of the female into the alimentary canal of the host and leaves this with the faeces.