INVERTEBRATES OF UNCERTAIN POSITION 



Plumatella and Pectinatella are fresh-water 

 ECTOPROCTA. The ENTOPROCTA have the 

 anal opening within the lophophore, and 

 the space between the intestine and body- 

 wall is filled with mesoderm cells. Pedicel- 

 Una and Urnatella belong to this group. 



8. PHORONIDEA 







This group consists of a single genus, 

 Phoronis (Gr. Phoronis, name of a king, 

 Fig. 125), containing worm-like animals 

 which live in the sand, enclosed in mem- 

 branous tubes. Their systematic position 

 is still more or less uncertain, but their 

 structure indicates a probable relationship 

 to the ECTOPROCTA. 



9. BRACHIOPODA 



FIG. 125. Phoronis 

 buskii (of the group 

 PHORONIDEA) removed 

 from its. tube and seen 

 from behind. (From 

 , Sedgwick, after M'ln- 



The BRACHIOPODA (Gr. brachwn, the tosn .) 

 arm; pous, a foot) are marine animals 

 living within a calcareous bivalve shell (Fig. 126). They are 

 usually attached to some object by a peduncle (Fig. 127, 10). 



B 



FIG. 126. Magellania flavescens (of the group BRACHIOPODA). A, dorsal 

 aspect of shell. B, shell as seen from the left side. b, beak; d.v., dorsal valve; 

 /, foramen; v.v., ventral valve. (From Weysse, after Davidson.) 



