320 
SIDNEY F. HAEMEE. 
and Phoronis, and if any affinity between the two does really 
exist, it follows that the Brachiopoda are not totally unre- 
lated to the Polyzoa, although the question still remains 
whether the latter approach most closely the Trochospheres of 
Chsetopoda, Mollusca, Phoronis, or Brachiopoda. 
Judging by the descriptions we at present possess, the Bra- 
chiopod larva is much further removed from the Trocho- 
spheral type than those of any of the other groups we have 
considered. If the points in which it differs from the typical 
Trochosphere are such as imply a real dissimilarity, and are 
not merely secondary larval characters, then it follows that the 
similarities between the Brachiopoda and the Polyzoa have 
no phylogenetic significance. The character of the lopho- 
phore has always formed one of the main reasons for associat- 
ing together the Polyzoa and the Brachiopoda, and its 
arrangement in the form of a horse-shoe in Argiope (for 
instance) and the Phylactolmmata has usually been con- 
sidered a proof of tlie affinity of the two groups. If, however, 
the Phylactolaemata are not so primitive as the Ento- 
procta, the hippocrepian character of their lophophore cannot 
be regarded as an archaic feature, but has been secondarily 
acquired. It seems to me, however, that a comparison between 
the developmental history of the Polyzoa and that of the 
Brachiopoda serves to show a considerable difference in the 
lophopliores of the two groups. In Argiope ( vide Oehlert 
and Deniker’s abstract of Kowalevsky’s Russian paper. No. 
40), after the mantle lobes have turned forward and the ten- 
tacles have begun to make their appearance, the young 
Brachiopod has a striking superficial resemblance to an adult 
Loxosoma. But by comparing the latter with its larva, we 
find that its lophophore replaces the larval ciliated ring, and 
that the head is outside the circlet of tentacles. In Argiope, 
however, the mantle lobes are developed entirely behind the 
cephalic segment which bears the eyes, and probably repre- 
sents the head, so that when they bend forwards after fixation, 
the part of the body bearing the eyes remains within the 
mantle cavity, a condition entirely different from that of 
