KOFOID AND SWEZY: UNARMOKED DINOFLAGELLATA 47 



West (1916) concludes that the nvitrition of the colored fomis is holophytic. 

 One of the most highly colored species found in the Gjinnodinoidae is seen in 

 Gyninodiniiim lineopnuicum (pi. 6, fig. 65), in which the remains of an ingested 

 Pouchetia are found occupying the anterior part of the body. In G. violescens 

 (pi. 6, fig. 69) also food Ijodies are present, though not definitely recognizable 

 as distinct organisms. Other species in this group showing the same indications 

 are G. contractuni (pi. 5, fig. 52), G. sulcatum (pi. 8, fig. 83), and G. rubricauda 

 (pi. 8, fig. 88), the first two of which contain bodies still surrounded by a 

 definite vacuole. In G. i)icisHiii (pi. 3, fig. 27) the remains of a Pouchetia with 

 the ocellus still visible clearly indicate the origin of many such bodies in the 

 plasma of these forms as the partly digested remains of ingested organisms. 

 It is thus evident that color alone can not be taken as indicative of the t^q^e 

 of nutrition which may be possessed by the organism displaying it. Further 

 evidences of this will be found in the genera CocJtlodinium and Pouchetia. 



In the remaining species of Gymnodinium comprised in the subgenera, 

 Pachydinium and Lineadinium, the absence of chromatophores is quite general 

 and indicates saproph}i:ic or holozoic nutrition for most if not all of these 

 species. In Gymnodinium hclveticuin (fig. Y, 11) Penard (1891, pi. 5, fig. 13) 

 has figured an ingested rhizopod, Diffiugia arcula. For most of the species of 

 the subgenus Pachydinium (figs. Z, AA) nutrition seems to be holozoic. In 

 Gymnodinium lira (pi. 3, fig. 30) we find an unusual condition in the ingestion 

 of what appears to l^e a grain of saud, which fills a large part of the body. 



Dogiel (1906) found food bodies present in both G. coeruleum and G. hete- 

 rostriatum (G. ohtusum). In the latter species our own material has offered 

 abundant evidence of its preference for solid food. Plate 5, figure 56, shows 

 such an one which had captured a Cochlodinium individual. Members of this 

 species were numerous in many hauls throughout the summer at La Jolla, and 

 in only a few cases was the body free from such ingested material. The size 

 of the ingested organism was often huge, and under the stress of conditions in 

 the microscopical field it would frequently be ejected from the body by a vent 

 at the antapex. During this process, which occupied but a moment, the entire 

 posterior end of the body was rent open, presenting a similar appearance to 

 that shown in Pouchetia maxima (pi. 6, fig. 61). This vent hnmediately began 

 to dra^\■ together and in a few minutes had completely disappeared, the body 

 resuming its normal outline at the antapex. The ingestion of these huge bodies 

 has not been observed, l)ut it is probable that it takes place l)y an amoeboid- 

 engulfing action of the sulcal area similar to the process noted in other flagel- 

 lates, as in Tetratrichomonas prowazeki (Kofoid and Swezy, 1915). 



In the genus Gyrodimum the number of species with clii-oinatoijhores is 

 very small, both relatively and muncrically. The same possibility of the union 

 of both holophytic and holozoic nutrition previously noted is suggested in 

 G. melo (pi. 5, fig. 50) with its green cliromatophores and large food body. 

 G. intortum (fig. CC, 10), whose green color might indicate a vegetable method 



