PENTACTAD.E. 



71 



Three rows of suckers placed on an oblong 

 crawling disk ; the other two rows rudi- 

 mentary Psolidce. 



No suckers Synaptada. 



FAMILY I. PENTACTAD^. 



Pentacta (Agass.). Suckers alternate in each 

 row, close-set; tentacles ten; dental apparatus 

 composed of nearly square plates ; no gizzard. 



P. frondosa. 



pentactes. Fig. 112; \. 



communis. 



fusiformis. 



hyalina. 



Drummondii. 



P. Hyndmanni. 

 fucicola. 

 Montagui. 

 Neiffii. _ 

 dissimilis. 



Ocnus (Forbes). Body regular, five-sided, 

 with five rows of distant suckers on the angles ; 

 tentacles ten ; dental apparatus very short ; a 

 gizzard. 



0. brunneus. Fig. 113; n. s. 0. lacteus. 



117 



115 



