KOFOID AND SWEZY: UNARMORED DINOFLAGELLATA 451 



rudiment. It is one of the simplest species of the subgenus PoucheticUa with 

 occlkis of tlie eoueentrated or integrated type and has no nearly related species 

 in so far as proportions, furrows, and ocellus reveal relationships. 



Pouchetia parva Lohmann 



Text figure PP, 6 



Pouchetia parva Lohmann (1908), pp. 147, 202, 252, 264, 366, table B, pi. 17, tig. 23. 



Figure inverted. 

 P. paron, Lohmann (1908), p. 369. Lapsus. 

 P. parva, Paulsen (1908), p. 106, fig. 148. Figure inverted. 

 P. parva, Lohmann (1911), pp. 30, 31, pi. 1, fig. 5; pi. 4, fig. 12d. 

 P. parva, Ostenfeld (1913), p. 338. 

 P. parva, Lebour (1917&), p. 198. 



Diagnosis. — A minute species, irregularly and as}anmetrically ovoidal, its 

 length 1.6 transdiameters ; girdle making prohalily 1.5 turns with considerable 

 displacement; sulcus unknown; ocellus postmedian, lens spheroidal irregularly 

 laminate, melanosome pyriform in outline; color, ochraceous. Length, •33/'. 

 Baltic at Kiel ; Plymouth Sound. 



Description. — Lohmann 's (1908, 1911) figures of this small species are so incomplete as to 

 make even its generic allocation a matter of uncertainty, especially since the girdle and sulcus 

 are not shown. The following account is based on his figure interpreted in the light of our 

 comparative knowledge of the genus. 



The body is irregularly ovoidal and asymmetrical, or even almost biconical in its contour, 

 with the shorter cone or broader end anterior. Both Lohmann (1908, 1911) and Paulsen (1908) 

 invert the figure and place the pointed end anterior. However, the relations of the ocellus are 

 in harmony with those elsewhere in the genus if we invert Lohmann 's figure, place the pointed 

 end posterior and thus point the lens anterosinistrally. The indications of the girdle also favor 

 such an interpretation. The length is 1.6 transdiameters at the widest part which is anterior to 

 the girdle and to the middle. The epicone appears to exceed the hypocone in size. The epicone 

 is convex subcouical with an angle of about 50" and a broadly rounded apex. The hypocone 

 has about the same angle, is less symmetrical, more prolonged, protuberant near the ocellus, 

 excavated below it, and tei-minates in contracted, bluntly pointed antapex, reflexed to the right 

 and dorsally. 



The absence of the ochraceous color in this antapieal tip in Lolunann's (1911, ])1. 4, fig. 12d) 

 third figure of this species appears to be an oversight. Otherwise one might interpret it as a 

 developing cyst detached only posteriorly from the surface pellicle of the body. In his second 

 figure (1911, pi. 1, fig. 5), drawn without a cyst wall, there is no suggestion that this extension 

 is not a part of the body, and in the original figure (pi. 17, fig. 23) it is colored with the same 

 ochraceous tint as the remainder of the body. 



The girdle is not portrayed sufficiently to enable one to define its course with certainty. It 

 forms a descending left spiral. The asymmetrical antapex is suggestive of at least 1.5 turns 

 and a displacement of about 0.75 transdiameter. The furrow, as drawn, is only slightly im- 

 pressed. The sulcus is not indicated in any way, unless it be that the line across the antapex 

 represents a posterior turn of this groove somewhat as in Nemaiodiinuin. If this be sulcus there 

 mav be at least a full turn of the sulcus about the body. 



