28 TEANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



posterior to the girdle, but overhung by projections from 

 either side. Longitudinal flagellum usually lying within the 

 sulcus and extending beyond the antapex for a distance 

 nearly as great as the whole length of the body. 



Body colourless and of a glassy transparency. Nucleus 

 probably situated near the centre of the body slightly to the 

 left of the middle line. Coloured (usually red) bodies, which 

 probably consist of food matter, often present in the region of 

 the sulcus. Length about 15G>. 



This species seems to be on the border line between the 

 genera Amphidinium and Gymnodinium, and it is doubtful 

 to which of them it should be referred. 



Amphidinium scissum, Kofoid. This species occurs 

 frequently, though never in large numbers, on the south end of 

 the beach, especially round the inner harbour and off the end 

 of the little pier. 



Description. Body ovate, dorsoventrally com- 

 pressed. Length about 1*8 to 2 transdiameters. Apex 

 flattened and sloping to the right, traversed by the sulcus, 

 which crosses the apex and swings round to the left, encircling 

 a small terminal button. Hemispherical outline of the antapex 

 broken by the deep semicircular notch at the posterior end of the 

 sulcus ; this notch lies a little to the right of the main axis 

 and the left margin is the longer one. Girdle forms a descending 

 left spiral, the proximal and distal ends of which are deflected 

 posteriorly at angles of about 30° and 45° respectively with the 

 horizontal. Distal displacement posteriorly about twice the 

 width of the girdle. Sulcus runs the whole length of the body, 

 terminating anteriorly in a sinistral loop around an apical 

 button and flaring posteriorly in the antapical notch. Longi- 

 tudinal flagellum extends posteriorly beyond the antapex 

 for a distance equal to the length of the body. Nucleus 

 ellipsoidal and posterior. Red and brown food masses fre- 

 quently present in region of sulcus. Body colourless or very 

 faint greenish grey. Length about 100/i. 



