Introduction to Animal Morphology. 227 



through the intestinal wall. The fluid is aerated at 

 the tentacles or body surface. 



Each persona has a yellow, oval or lobed ganglion 

 between the mouth and anus, sending two strong 

 branches to the tentacles and two to the cesophagus, 

 round which they make a ring (Fredericella, &c.) 

 Below this may be a sub-oral, pharyngeal ganglion in 

 . cases (Dumorticr}. Serialaria and other cteno- 

 stomatous, branched forms have a colonial nerve-system, 

 taking its origin from a ganglion at the base of each 

 branch of the stock, which unites by fine plexiform 

 branches with the nerves of each persona. This ex- 

 plains the consentaneous action noticed in a colony 

 such as Mimosella. 



ial sense-organs exist, except perhaps the ciliated 

 body near the ganglion in Pedicellina ; but many colonies of 

 freshwater forms show by their motions that they are sensitive 

 to light. The muscular lamina is never complete, but con- 

 sists of specialized bundles, which arc ist, two retractors of 

 the lophophorc ; 2nd, retractors of the polypide, from the floor 

 of the cell to the cesophagus; these lie in the axis of the 

 pillar in Pedicellina ; 3rd, two rotators of the lophophore, in 

 the freshwater form ending in each corner of the crescentic 

 4th, retractors of the tentacles from the lophophorc, 

 placed between each pair of tentacles, sending a branch on 

 ; 5th, the levator of the epistome ; 6th, Parieto- 

 !is anterior, many short transverse bands from the 

 laird part of the endocyst to the protrusible part; 

 -inalis posterior, stronger, behind the last, to 

 -mancnt; 1 part of the endocyst ; 8ih, Parietalis, 



.interior fibres are tin 1 sphincter 

 these, tin-re are radiating fibres joining 

 Avicularia, and opcrcular muscles in 

 tomuin. 



The irregularly rounded t- cither seated 



Q2 



