432 MEMOIRS OF THE UNIVERSITY OP CALIFORNIA 



The genus Pouchetia shares Avith Cochlodinium the relative freedom from 

 longitudinal striae upon the surface of the body. These striae are common in 

 Gi/rodiiiiiim and Gij)ii)todi}tii()u, but are not associated in Pouchetia with primi- 

 tive or generalized species. Only three species have striae, P. striata, P. vio- 

 lescens, and P. maxima (tigs. 00, 8, 1, 2), all highly specialized forms. Sug- 

 gestions of an underlying but ordinarily invisible linear organization of the 

 cytojilasm appear in the faintly linear grouping of pigment granules in P. 

 macuhita (pi. 11, fig. 119), and the linear aggregates of pigment in P. violescens 

 (pL 11. fig. 118). 



The color of the c\i;oplasm in Pouchetia is remarkably diversified, change- 

 able in tone and in aggregation, and probably subject to considerable modifi- 

 cations as a result of internal physiological states and stages of metabolism 

 (cf. figs. 118, 120, pi. 11). It may be diffuse as in P. rulesccm (pi. 8, fig. 90), 

 P. purpurescens (fig. 84), P. pur pu rat a (fig. 87), and P. voracis (fig. 89) ; or 

 in sjiheroidal aggregates as in the black granules of P. maculata, or the greenish 

 flecks of P. pouclieti. 



Nearly the whole range of colors of the spectrum is to be found within the 

 species of this genus, but most of them near the red end. P. violescens (pi. 11, 

 fig. 118), P. juno, and P. maxima (pi. 6, fig. 61) lie near the violet end, exhib- 

 iting tones of violet and lavender. P. poucJieti (pi. 11, fig. 125) is bluish green, 

 P. atra (fig. 126) somewhat greenish, P. alba (fig. 121) faintly tinged with pale 

 yellow, P. fusus and P. parva are ochraceous, and the remaining twelve species 

 exhibit various shades of red, grading from the darker purples of P. purpurata 

 and P. purpurescens to the rosy tint of P. voracis. While there is no exact and 

 imiforndy graded parallelism between the colors of the species of Pouchetia 

 arranged in the scale of the spectrum from violet to red and the progressive 

 structural specialization of these species, there is, nevertheless, a sufficient dif- 

 ference to justify the conclusion that pigment formation is a feature of pro- 

 gressive specialization in these organisms, passing from the faintly tinged bluish 

 green to the red and black colors, and that this is accompanied by structural 

 specializations of the ocellus, sidcus, and girdle. The evidence is as follows: 

 (1) the simplest species with least integrated ocellus and most Gymnodinium- 

 like furrows, P. alha and P. poucheti are faintly tinged with bluish green and 

 yellow; (2) all the rose-red species, P. compacta, P. patiamensis, P. polyplicmus, 

 P. rosea (Pouchet), P. ruhesceus, P. striata, P. suhnigra, and P. voracis, and 

 the reddish-black P. maculata have well integrated ocelli, and a high degree of 

 complexity of girdle and sidcus. The two ochraceous species, P. fusus and 

 P. parva, are less specialized. There remains a group of purplish species, P. 

 purpurata. P. purpurcscois, and P. scliuctti. The first two of these are highly 

 specialized, the last less so. The two violet-lavender species, P. violescens and 

 P. juno, are highly specialized large species, and as such do not exhibit the 

 simplicity in structures shown in the general trend of the genus at the violet 

 end of the spectriun. The preponderance of evidence, however, suggests a 



