BRYOZOA, WITH DESCRIPTIONS OF NEW SPECIES. 399 
The set of muscles alluded to, as not passing into the pedicle 
comes from the perforate valve, and, inclining downwards, is 
attached by the other end, to the base of the imperforate valve 
binding the parts of the hinge-joint together—a substitute in 
fact, for a ligament. In some species, this set assumes in part, the 
function of an adductor muscle. 
We have then evidently some reason for supposing that the 
Brachiopoda, as well as the Ascidie, are related to the Bryozoa; 
and it is in this way that these latter are connected with the Za- 
mellibranchiata. After a careful examination of the Brachiopoda, 
it is impossible to doubt the connexion that exists between the 
two great divisions of the testaceous Acephala. Indeed this is 
evident, whether we look to the digestive organs, the vascular 
system, or to the reproductive apparatus. It is in these animals, 
too, that the respiratory organ is first found in connexion with 
the mantle, in Z'erebratula, quite rudimentary, in Lingula, to 
some extent specialized. On comparing Anomia with Orbicula, 
this relationship is best seen. In both, the mantle is completely 
separated, and in both it is connected with the ovary ; the large 
oral palpi of the one form the homologue of the branchial organs 
of the other; and we see this relationship in the deficiency of 
pedal organ in Anomia, and in the extensive union that still 
subsists between its breathing apparatus and the mantle: the 
perforation of the under-valve of both is also remarkable; but 
not more so than that the great muscle of both should be divided, 
part forming the adductor, part the adhesive disc. 
We have now endeavoured to trace the affinities of both 
branches of Bryozoa ; one appears to pass at once into the As- 
cidice, which, how closely soever related analogically to the Lamelli- 
branchiata, are nevertheless removed far from them, by the nature 
of their vascular, respiratory, and re-productiye systems, In the 
Mollusca, the heart is always systemic, and the gill is universally 
an appendage to the mantle. In the Asczdie, the heart is as 
much pulmonic as systemic, and the breathing apparatus is a de- 
velopment from the alimentary canal—is in fact pharyngeal. 
In these respects the Ascidian deviates from the Molluscan type, 
and approximates to that of the lower Vertebrata,—the fishes, in 
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