220 ACTINOZOA. 



gestive sac is relatively shorter than in other 

 Cteiiophora. In the Beroidce the funnel is very- 

 short and Tvide. Not more than one pair of apical 

 canals ever appears to have been noticed. 



2. Of paragastric canals, one or two pairs may 

 be present. The single pair of these canals are 

 caecal in Pleurohracliia ; in Beroe they open into 

 an oral tube. In most of the lobed Ctenophora 

 two pairs of paragastric canals occur, of which 

 one lies close to the sides of the digestive sac, the 

 position of the second pair being more superficial. 

 The inner pair may be cascal, while the outer pair 

 open into the oral tube ; or the latter may anas- 

 tomose with both pairs of paragastric canals, as 

 described by Milne Edwards in Chiajea Paler- 

 onitana. 



The oral vessel may be circular, as in the 

 BeroidcB, or consist of two straight canals run- 

 ning by the sides of the mouth, as in many of 

 the lobed Ctenophora; though in one of these, 

 Eurliamphoea, this vessel is complete. 



3. The eight ctenophoral canals may conve- 

 niently be divided into four lateral, and four 

 antero-posterior. 



The oral extremities of all these canals may be 

 caecal, as in PleurohracMa, or open into the cir- 

 cular tube surrounding the mouth, as in the 

 Beroidce. Among the lobed Ctenophora, the 

 same tube, or the two vessels its representatives, 

 receives only the extremities of the four lateral 

 canals. Thus, in Bolina, each of the latter, after 

 supplying the course of its comparatively short 

 ctenophore, ■^T.nds round the edge of one of the 

 smaller lobes or earlets, and having again reached 



