394 MEMOIRS OF THE UNIVERSITY OP CALIFORNIA 



OccuBRENCE. — Occasional in the jilankton taken ofE La Jolla, California, 

 in July and August, 1917, in hauls from 80 meters to the surface in surface 

 temperature of 19° C to 21 ?5 C. Eeported by Pouchet (1885fl) from the 

 Atlantic at Concarneau and by Miss Lebour (1917&) from Pl^^nouth Sound, 

 England, where it was abundant in July and August, and rarely even into the 

 winter months, during which it was the only representative of the Gymnodi- 

 nioidae found. The extreme variability noted by ]Miss Lebour may be due to 

 the inclusion of T. rohiistioii in this species. Schroder (1900) found it in July 

 and August in the plankton of the Bay of Naples; and Karsten (1907) records 

 it in one haul of the Valdivia Expedition, made from 100 meters to the surface 

 near the center of the Indian Ocean in March. It thus appears to be a eupelagic 

 species, prolxably of wide distribution in tropical and wann temperate seas. 



Comparisons. — This is the slenderest species not only of Torodiuium but 

 likewise of all of the free-living Gymnodinioidae. The shortening of the trans- 

 verse flagellum and of the girdle in which it lies has extended to such a degree 

 that the transdiameter of the body in this region is little more than 0.35 of that 

 of the widest part of the body, a region in Avliich the girdle is normally located 

 in most Gymnodinioidae. 



Syis^onymy. — This species was described as GymnodiniHm teredo by Pouchet 

 (1885«), and has been retained in that genus by all subsequent investigators 

 who have dealt with it. Schiitt (1895) did not sei^arate it from T. rohnstuni, 

 which he includes in his figures of T. teredo. This confusion appears to have 

 been continued by Lebour (1917Z>), and possibly others. 



