8 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 122 



obviously dead, so that the basal parts of the thickest carpets are 

 probably formed from collapsed and degenerating zoecia and con- 

 necting tubules held together by the adhesive substance secreted by 

 the filiform processes. Septa are more resistant than the rest of the 

 zoecium and are quite conspicuous in fuchsin-stained material as 

 loose red discs with a central perforation. Brown bodies are distrib- 

 uted irregularly through the tubular zoecia, indicating that the 

 animals grow by the successive death and replacement of several 

 polypides in the same zoecium. The space between zoecia is filled 

 with dense masses of detritus and sediment tightly cemented into 

 the colony by the remains of filiform processes and probably also by 

 an adhesive material produced on the cuticle itself. Filiform pro- 

 cesses are represented more sparsely on the zoecial walls than on the 

 exposed tips of the zoecia. It seems hkely that they are formed at 

 the growing tips and break down as the zoecium elongates distally 

 (figs. 4, 5). 



Muscular system. — Because the zoecia are tubular and because 

 the polypides are confined to the most distal portion of the upright 

 cystid, the tentacle sheath and vestibule are directly in line with one 

 another and the strong bilateral symmetry of the apertural muscles 

 seen in form A has been lost. The strong vestibular muscles probably 

 are associated with the habit of drawing foreign material into the 

 vestibule. Both the vestibular wall and the orificial collar are ex- 

 ceedingly sticky and large masses of foreign material, including sand 

 grains nearly as large as the diameter of the zoecium, are introverted 

 when the lophophore is retracted. As a result, the vestibules of all 

 zoecia old enough to feed are packed solidly w4th foreign material. 

 It has not been possible to ascertain how this material is eliminated 

 when the polypides degenerate, but none has been observed incor- 

 porated into brown bodies. 



The apertural muscles of form B arrange themselves radially 

 around the vestibule and show none of the bilaterality of form A 

 (see p. 5), 



In some species (e.g., Victorella pavida), the disposition of the 

 apertural muscles into four evenly spaced clusters imparts a quad- 

 rangular shape to the closed apertiu-e. Even the apertures of tightly 

 retracted zooids of Victorella argilla are puckered urregularly. It 

 should be noted that all other species of Victorella so far described 

 possess quadrate apertures (Braem, 1951). 



Digestive system. — Braem (1951, p. 23) attaches considerable 

 taxonomic importance to the location of the sphincter muscle of the 

 cardiac stomach. One of the principal reasons he gives for separating 

 the genus Tanganella from Victorella is that the sphincter muscle of 

 the latter is placed near the middle of the cardiac stomach while, in 



