260 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 2 



Family Baseodiscidae 



Genus BASEODISGUS Dfesing 



Four species of this genus have been reported from the North Pacific 

 coast. 



Key to Species 



1. With narrow transverse rings of vi^hite throughout length of 

 body. Body of moderate diameter but may be of great length, 

 sometimes exceeding 2 m; red or brown, with numerous narrow 

 white rings encircling the body ........ mexicanus 



1. Without white rings 2 



2. Longitudinally striated with numerous interrupted and irregu- 

 larly anastomosing, very narrow black or dark brown lines 

 delineatus 



2. Without longitudinal striations 3 



3. Yellow, thickly sprinkled with small, irregular, dark red spots; 

 body may reach very large size, sometimes 2 m or more in length 

 princeps 



3. Deep red, orange red, mahogany, or reddish brown, sometimes 

 covered with whitish bloom ; anterior portion of head with 

 broad spot of darker color, bordered terminally and laterally 

 by white punnetti 



12. Baseodiscus delineatus (Delle Chiaje), 1823-1829 



Polia delineata Delle Chiaje, 1823-1829; Eupolia delineate Burger, 

 1895 ; Baseodiscus delineatus Burger, 1904. 



Habitat. Beneath stones and among corals and other growths as well 

 as in sand near low-water mark and below. 



Distribution. One of the most widely distributed of all species of 

 nemerteans, being reported from both Northern and Southern hemi- 

 spheres and under widely diverse temperature conditions; Mediterranean 

 to Cape Verde Islands, Mauritius, Fiji Islands, Barbados, Bermuda, 

 Chile, Gulf of California. One specimen, about 30 cm in length and 7 mm 

 in width, was collected by the Allan Hancock Expedition of 1937 on the 

 shore of San Francisco Island and another at Espiritu Santo Island, both 

 in the Gulf of California. 



