290 MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



The wliole body is suffused -with a primuline yellow tint fading in the antapieal process to a 

 light chalcedony yellow. 



The body is enclosed in a very thin and exceedingly transparent cyst wall which is closely 

 applied to the body, even sinking into the furrow of the girdle. About the apical and antapieal 

 processes it is distended and is prolonged bej'ond each in tinger-like processes of equal length, 

 about 0.66 that of the body. This distension indicates a difference in the osmotic properties or 

 capacities of the membrane in these regions or a localized permeability of the body permitting 

 greater exudation in these terminal surfaces. 



DiMExsioxs. — Length, of body 66,'^, of total cyst 137/^ ; trauscliameter, 33/^. 



OccuEREXCE. — Described from a single individual taken in a haul of a No. 

 25 silk net from 80 meters, 4 miles offshore at La Jolla, California, in the 

 California Current in surface temperature of 19-8 C on July 9, 1917. It was 

 again found July 23, in a haul 6 miles offshore in 80 meters to the surface and 

 a surface temperature of 20-8 C. 



CoMPARisoxs. — This species bears a superficial resemblance to Gymnodinium 

 fusus Schiitt (1895, pi. 24, fig. 79, pi. 25, fig. 81). yet differs from both the forms 

 which Schiitt has figured under this name, the first of wMch is a Gymnodinium, 

 the second we have placed in Gyrodinium as G. falcatum nom. sp. nov. Our 

 species resembles G. falcatum (fig. CC, 11) in the presence of distinct apical 

 processes which are distinct from the midbody and blunt at the ends, features 

 wliich distinguish these two species from all other fusiform species of the genus. 

 There is a possibility that there might be some change in form incident upon 

 release from the cyst, yet such changes have not occurred in our material except 

 in one individual in which the body was filled with large food masses. This 

 was enlarged posteriorly but without change anteriorly. Schiitt 's form shows 

 many yellow-ochre chromatophores which are totally lacking Ln our species. 

 It was also larger, measuring 122/^ as compared with 66^, the length of our form. 



Gryrodinium concentricum (Lebour) 



Text figures EE, 1, 2 

 Spirodinium concentricum Lebour (19176), p. 194, fig. 11. 



Under this name ^liss Lebour has figured a Gyrodinium characterized by 

 concentric lines arranged aroiind a certain point on the side or dorsal surface 

 of the body. The body is colorless with a shape and girdle arrangement like 

 G. ohtusum Schiitt. This is evidently a species of Gyrodinium parasitized by 

 a species of A)noehop]irya Ivoi^pen. Forms parasitized by some member of this 

 genus have been observed in our own material and present the coiled appearance 

 shown in Lebour 's figure. This explanation seems to be borne out by her own 

 statements of the inconstancy in position of the spiral, the variations in size of 

 tlie organism and that it was of rare occurrence. Sufficient data are not given 

 to identify the Gyrodinium; we, therefore, place it among the species of doubtfid 

 status as undeterminable. 



