FAUNA OF THE ALEUTIAN ISLANDS AND ALASKA PENINSULA 371 



3 centimeters deep. Muscle fibrils can be seen extending into 

 these lobes in bundles of 12 or more. 



A number of small medusae were collected in plankton hauls, 

 including Aegina, Hybocodon, Mitrocoma? , Rathkea, Sarsia, and 

 Stomotoca. 



FLATWORMS 



A monogenetic fluke, Entobdella hippoglossi, was collected 

 from the skin of a halibut (Hippoglossus stenolepis) off Nikolski, 

 Umnak Island, on August 30, 1938. (See also Annelid Worms.) 



ROUNDWORMS 



Sperm whales (Physeter catodon) brought to the Akutan whal- 

 ing station are, without exception, infested with intestinal worms. 

 According to Coast Guard Inspector A. Van De Venter the baleen 

 whales are commonly infested as well. Anisakis physeteris was 

 collected from the intestine of sperm whales here (Scheffer 1939) . 



Contracaecum clavatum is a thready white worm found in 

 masses in the stomach of nearly every cod (Gadus macrocephalus) 

 examined in Aleutian waters. A single specimen of Cystidicoki 

 sp. was also collected in the cod. Porrocaecum decipiens was 

 found encysted in larval stage in the mesenteries of the cod. 



An undetermined species (larval) of Porrocaecum was taken 

 from the stomach of a sea otter. 



NEMERTEAN WORMS 



Paranemertes peregrina is a long, thready worm found in the 

 tidal zone under rocks; it is colored dark brown to purple above 

 and white to yellow below. 



BRACHIOPODS 



Three specimens of a single species, Diestothyris frontalis, were 

 collected. 



ANNELID WORMS 



Two leeches from the skin of fishes were collected : Ottoniobdella 

 scorpii is a cream-colored worm, 25-50 millimeters long, com- 

 monly found attached to the dorsal surface of the sculpin 

 (Hemilepidotus). Platybdella quadrioculata was collected once, in 

 the operculum of a cod (Gadus macrocephalus) . 



Many free-living worms doubtless are present in the sand and 

 among the tide-pool rocks of the Aleutian beaches, but the col- 

 lections of the present expedition have not been studied. A species 



