Morse.] 316 (March 19, 
dea, first separated by Milne Edwards, and afterwards adopted by 
Dana, with pregnant suggestions as to its value as a group by itself. 
Recently Kowalewsky, Kupffer, Schultze and others, have as- 
sailed the Tunicata, and demonstrated their kinship with the lower 
Vertebrata through Amphioxus. Leuckart has long maintained 
that the Polyzoa have no sort of relation to the Mollusca, but belong 
to the Vermes, and recently the distinguished Gegenbaur, in the sec- 
ond edition of his Outlines of Comparative Anatomy, not only assigns 
the Polyzoa to the Vermes, but places there also the Tunicata. And 
now in this paper I wish to show that in every point of their — 
structure, the Brachiopoda are true worms, with possibly some affin-— 
ities-to the Crustacea, and that they have no relations to the Mol- 
lusca, save what many other worms may possess in common with them. 
In nearly every case the unnatural association of certain groups 
with the Mollusca has been due entirely to superficial resemblances, 
to ‘“‘ formal analogy,” as Forbes would say. 
The same reason that first led conchologists and zodlogists to in- 
clude Spirorbis and Serpula and the Cirripedia, as well as the For- 
aminifera, with the Mollusca, namely, the presence of a calcareous 
shell, also brought the Brachiopoda into the same category. But 
while there was some resemblance between the cases of certain tubi- 
colous Annelids and the shell of Vermetus, or the flattened form 
and lateral shells of Anatifa, and the lamellibranchiate shell, or the 
chambered shell of certain Foraminifera and the Nautili, there was 
but little to suggest an affinity with the lateral lamellibranchiate 
shells, in the dorsal and ventral plates of the Brachiopoda. 
The mere possession, however, of a calcareous shield of some sort, 
whether in one piece, or several pieces, whether a tubular or a cham- 
bered shell, furnished sufficient reasons for most zoologists to include 
creatures bearing such shelly coverings with the Mollusca. Hence 
we find Lamarck, at one time placing Anomia and Discina together. 
And Cuvier, allowing the accepted views of the time to lead him 
astray, forsook his principles based upon internal structure, and re- 
garded the relations of the Cirripedia as molluscan. 
It is amusing now to look back and see with what quiet resignation 
the conchologists (for such they were rightly called) permitted the 
removal of those forms which possessed no shelly covering, with what 
stolid indifference they allowed other unprotected forms being forced 
upon them, and with what obstinate pertinacity they withstood the 
removal of such groups as possessed a limy shell. 
