With no hinge to the shell and with an alimentary canal open at both ends, and Testicardines (Articulata), with a hinge between the dorsal and ventral valves and with no anus, was proposed by Owen and has been adopted by nearly all authors.
The stomach then passes into an intestine, which in the Testicardines (Articulata) is short, finger-shaped and closed, and in the Ecardines (Inarticulata) is longer, turned back upon its first course, and ends in an anus.
The orders Atremata and Neotremata are frequently grouped together, as the sub-class Inarticulata or Ecardines - the Tretenterata of Davidson - and the orders Protremata and Telotremata, as the Articulata or Testicardines - i the Clistenterata of Davidson.
TESTICARDINES (ARTICULATA) ORDER III.
ARTICULATA, a zoological name now obsolete, applied by Cuvier to animals, such as insects and worms, in which the body displays a jointed structure.
- Zooid of Paludicella articulata (= ehrenbergi).
- Dicyclica in which the dorsal cup primitively is confined to the patina and occasional intercalated anals, and no other plates ever occur between RR (Grade: Distincta); Br may be incorporated in the cup, with or -without iBr, but never rigidly, and their corresponding ambulacrals remain supra-tegminal (Grade: Articulata); new columnals are introduced at the extreme proximal end of the stem.
This primary group was set up to indicate the residuum of Cuvier's Articulata when his class Annelides (the modern Chaetopoda) was removed from that embranchement.
We have, in fact, returned very nearly to Cuvier's conception of a great division or branch, which he called Articulata, including the Arthropoda and the Chaetopoda (Annelides of Lamarck, a name adopted by Cuvier), and differing from it only by the inclusion of the Rotif era.
The name Articulata, introduced by Cuvier, has not been retained by subsequent writers.