52 BULLETIN OF THE MUSEUM OF COMPARATIVE ZOOLOGY. 



EXPLANATION OF THE PLATE. 



Fig. 1. Sti/Iochoplana californica, from specimen cleared in glycerin to sliow the 

 liabit. X 22. bu., bursa ; in., lateral branches of the intestine ; o., mouth ; 

 pe., penis; phy., pharynx; <., tentacles ; (J, male gonopore ; 9 > female 

 gonopore. 



Fig. 2. Enlarged drawing of the brain to show the arrangement of the eye-spots and 

 their relation to the tentacles and cerebral nerves. 



Fig. 3. Pi-osthecerceus panamensis. Anterior end showing the cerebral eye-mass and 

 tentacular eye-spots. X 27. Owing to the condition of the specimen the 

 anterior margin of the body appears turned under, looking as if the ten- 

 tacles sprang from the ventral surface of the animal. 



Fig. 4. Rhabditi and Pseudorhabditi of the same species, from a bit of teased 

 hypodermis. X 700. 



