CHAPTER XVIII 



POUCHETIIDAE : PROTOPSIS, XEMATODINIUM 



Family 5. POUCHETIIDAE fam. nov. 



DiAGxosis. — G^Tiinoclmioidae with ocellus located on left side of tlie inter- 

 ciugular sulcus, cousisting- of a lens and melanosome or pigment mass ; epicone 

 and liYi:)ocone are subequal ; girdle and sulcus with more or less torsion ; pusules 

 usually present ; plasma usually colored. Length, 32-lJ:l,". All eupelagic and 

 marine and are Icnown principally from warm temperate and tropical seas and 

 rarely in purely neritic waters. 



Descbiptiox 



The ocellus is located on the left side of the iutercingular sulcus, and consists 

 of a lens and melanosome or pigment mass, the latter often amoeboid, and 

 usually differentiated in the center into a red, brown, or yellow region or 

 sensory core. The pigment mass is red throughout in some instances. The 

 epicone and h^-^)ocone tend to be subequal except in Enjthropsis, where the 

 epicone is reduced. The girdle and sulcus in some cases show considerable 

 torsion, and the latter often has an apical and an antapical loop. Paracingular 

 lines are present in Erythropsis. Var\nng degrees of integration of the ocellus 

 occur throughout the genera of this family. Xematocysts are present in 

 Nematodinium. A posteriorly directed prod or tentacle is formed in Proteri/- 

 thropsis and Eri/thropsis. Pusules are often present, opening anteriorly into 

 the anterior and posteriorly into the posterior flagellar pores. The nucleus 

 generally lies anterior to the ocellus and may or may not have a perinuclear 

 membrane. Longitudinal striae on the surface of the body are rarely present. 

 Vacuoles tend to form in the peripheral plasma. 



The plasma is often highly colored, especially peripherally. Cyst formation 

 is very frequent, the closely adherent membrane becoming distended after its 

 formation by an intramembranous fluid. The body itself within the cyst does 

 not become inflated with intracytoplasmie vacuoles. 



It contains five genera: Protopsis with 3 species, Nematodinium with 3, 

 Pouchetio with 20, Proterythropsis with 1, and Erythropsis with 10, making a 

 total of 37 species. Of these five genera three are new, Protopsis, Nemato- 

 dinium, and P rot enjthropsis. Erythropsis was described by Hertwig (1884), 

 though its affinities with the Dinoflagellata long remained unrecognized, and 

 Pouchetia was proposed by Schiitt (1895) for the ocellate G^^lmodinioiclae, 

 including tv\'o species now referred to Erythropsis, whose affinities he did not 

 recognize. 



[414] 



