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SIDNEY F. HAEMEE. 
open dorsally on the praeoral lobe, between the brain and the 
mouth ! 
Lankester (45 and 49) has adopted Caldwell's explanation of 
the surfaces of the Polyzoa as the most probable which has 
been suggested ; the buccal shield of Rhabdopleura, and 
therefore, one may conclude, the large epistome of Loxo- 
soma, being considered possibly a representative of the mantle 
area. 
Lankester's earlier opinion (7 and 8) on the relations of the 
surfaces of the Polyzoa is well known, the epistome being 
homologised with the foot, and the foot-gland with the shell- 
gland of Mollusca. This opinion has of course been re- 
nounced in accepting Caldwell's view of the Polyzoa. 
Balfour (28) has urged two difficulties against the view of 
the homology of the foot-gland (undoubtedly the same organ 
in both the adult and the larva of Loxosoma) with the 
Molluscan shell-gland. These difficulties are — (i) the ciliation 
of the foot- gland of the larva ; (ii) its relation to the velum. 
The sucker of the larva of the Entoprocta is not, however, 
invariably ciliated ; it is indeed surrounded by a circlet of stiff 
hairs, probably tactile like the sense hairs of the adult Loxo- 
soma or of the larval Pedicellina; but it seems quite 
natural to suppose that special tactile organs would be advan- 
tageously localised in the neighbourhood of any apparatus 
commonly used for the temporary attachment of its possessor 
o foreign objects. The presence of these sensory hairs, quite 
similar to those occurring in other regions of the body, need in 
itself form no valid objection to Lankester’s (former) view. 
The shell-gland of Mollusca is not used for attachment, and 
does not require a development of these tactile hairs. 
The objection which refers to the position of the velum 
appears to me of a more serious nature. The ciliated ring of 
Loxosoma has generally been regarded as homologous with 
the velum of Trochospheres, and on this supposition the 
ciliated furrow running along the inner border of the ring (in 
the larva of Loxosoma) and produced by means of the oral 
groove into the (Esophagus, corresponds with the similar ciliated 
