Ranarum is found in the alimentary canal of the frog and growing on its excrement.
Schizomycetes exist in every part of the alimentary canal of animals, except, perhaps, where acid secretions prevail; these are by no means necessarily harmful, though, by destroying the teeth for instance, certain forms may incidentally be the forerunners of damage which they do not directly cause.
The alimentary canal is uncoiled and cylindrical, and gives rise laterally to large gastric glands, which are more than a single pair in number (two to six pairs), and may assume the form of simple caeca.
A, Edge of groove formed by adhesion of median dorsal surface of alimentary canal to sheath of notochord; b, median dorsal surface of alimentary canal; c, left dorsal aorta; cc, single dorsal aorta, formed by union of the two anterior vessels; cc', same vessel resting on intestine; d, cut edge of pharyngo-pleural folds of atrial tunic, really the original outer body-wall before the downgrowth of epipleura; d', atrial tunic (original body-wall) at non-perforate region, cut and turned back so as to expose peri-enteric coelom and intestine r; e', upstanding folds of body-wall (pharyngo-pleural folds) on alternate bars of perforate region of body; f, atrio-coeiomic canals or brown funnels (collar-pores of Balanoglossus); g, cavity of a gonad-sac; m, cut musculature of body-wall; n, anus; o, post-atrioporal extension of atrial chamber in form of a tubular caecum; p, atriopore; q, hepatic caecum; r, intestine; s, coelom; t, area of adhesion between alimentary canal and sheath of notochord; v, atrial chamber or branchial cavity; w, post-atrioporal portion of intestine; x, canals of metapleura exposed by cutting; E, probe passing through atriopore into atrial or branchial chamber; FF', probe passing from coelom, where it expands behind the atriopore, into narrower perienteric coelom of praeatrioporal region.
The embryo thus passes from the body of the female into the alimentary canal of the host and leaves this with the faeces.
Didelphia, the alternative name of the group was given in allusion to the circumstance that the uterus has two separate openings; while other features are the inclusion of the openings of the alimentary canal and the urino-genital sinus in a common sphincter muscle, and the position of the scrotum in advance of the penis.
In all known Pantopoda the size of the body is quite minute as compared with that of the limbs: the alimentary canal sends a long caecum into each leg (cf.
In the adult aquatic stage the alimentary canal shows signs of degeneration, and it seems probable that in this stage Gordian worms take no food.
In spite of these difficulties it must be conceded that the dorsal flexure of the alimentary canal of the Pterobranchia is very Phoronis-like.
A considerable part of the alimentary canal is said to be derived from the ectoderm in the buds of both Cephalodiscus and Rhabdopleura.