420 MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



P. schuetti nom. sp. nov., Schiitt's (1895) forms differ from Pouehet's (1887) 

 in having the torsion of Pouchetia and a rosy instead of an ochraceous plasma. 

 The oceUus of P. schuetti is compound as in Protopsis nigra, but none of 

 Schiitt's figures of his "P. rosea" has peripheral black pigment. As matters 

 stand Pouehet's (1887) figures nmst be assumed to be correctly drawn until 

 some one rediscovers his species and critically reexamines it in the light of 

 later data and these criticisms. 



Protopsis ochrea (Wright) 



Text figure LL, 4 

 Pouchetia ochrea Wright (1907), p. 4, pi. 1, tig. 8. 



Diagnosis. — A small species of rotund body, its length 1.2 transdiameters ; 

 girdle equatorial, displaced about 0.25 transdiameter ; sulcus?; ocellus simple, 

 lens conical campanulate with terminal projection, melanosome lobed; chro- 

 matophores linear, ochraceous. Length, 55/^. Canso, Nova Scotia, July. 



Description. — Ouly one individual in binary fission prior to mitosis is figured by Wright 

 (1907), so that the possibility of an adequate comparative description is much restricted. The 

 body is rotund, its length about 1.2 transdiameters, with epieone and hypocone subequal. 

 Epicone subhemispherieal, hypocone less hemispherical with antapex slightly longer at the right, 

 but broadly rounded. 



Girdle nearly equatorial, not overlapping, without torsion of the body, intercingular dis- 

 placement about 0.25 transdiameter, furrow shallow with prominent lips. Sulcus not figured, 

 but probably nearly straight and midventral. 



Ocellus simple, located at the left of the intercingular sulcus with its main axis oblique, 

 deflected about 40° from the median plane to the right anteriorly, its length 0.4 transdiameter. 

 Lens simple with campanulate base bearing a short, terminal, anteriorly directed stem about half 

 the length of the base, the bottom of which is buried in the shallow melanosome which bears on 

 its posterior face five or six simple or branched lobes or processes. Chromatophores ochraceous, 

 in strands as in Schiitt's Gymnodinium geminatum. Nucleus (food ball?) ellipsoidal, its length 

 about 0.33 transdiameter. Binary fission in close fitting gelatinous cyst. 



Dimensions. — Lengili, 55m; ti*ansdiameter, 45m; leng-th of ocellus, 22/*. 



Occurrence. — Common in the plankton at Canso, Nova Scotia, in July, 

 1901-02 (Wright, 1907). 



Comparisons. — Differs from all known Pouchetiidae in having chromato- 

 phores and therefore in being in all probability holophytic. The tji^e of ocellus 

 distinguishes it at once from the other species of this genus, P. nigra (Pouchet). 

 However, the peculiar form of the lens and the much lobed melanosome are 

 indicative of a near ai3proach to or only a slight differentiation from the com- 

 pound type. This species also lacks the distributed peripheral pigment strands 

 so characteristic of P. nigra (fig. LL, 1). 



