KOFOID AND 8WEZY: UNARMORED DINOFLAGELLATA 379 



Cochlodinium rosaceum sp. uov. 



Plate 8, figiire 85 ; text figure HH, 4 



Diagnosis. — A mediuni sized species with ellipsoidc^l body, its length 1.48 

 transdiameters ; girdle a descending left spiral of 1.5 turns, displaced 0.85 trans- 

 diameter; sulcus with torsion of 0.5 turn : color, rose red. Length, 63/^. Pacific 

 off La Jolla, California, July. 



Description: — The body is rotund ellipsoidal, with broad apices, nearly circular in cross- 

 section, the dorsal side more convex than the ventral, its length 1.48 transdiameters at the 

 widest pai't. The epicone exceeds the hypocone in size, its length being greater by 0.26. The 

 epicone is subhemispherical in shape, with a length from the proximal and distal ends of the 

 sulcus of 0.28 and 0.88 respectively of the total length of the body. Tlie hypocone is rounded, 

 with broad, somewhat flattened antapex indented by a wide suleal notch. 



The girdle is a descending left s]iiral lying at a distance from the apex of 0.28 and 0.88 

 respectively of the total length of the body. In the first transdiamcter of its course it is deflected 

 anteriorly, gradually turning posteriorly at an angle of about 35° with the transverse plane. 

 At its distal end its direction is nearly transverse. The furrow is narrow, varying somewhat 

 in width, its average about 0.04 transdiamcter, and is rather shallow, with smooth borders. The 

 sidcus arises near the apex and extends posteriorly in a left, spirally deflected course with a 

 torsion of slightly more than 0.5 turn. The furrow is narrow in widtli and shallow, but in the 

 intei-cingular area it lies at the base of a deep constriction of the body, and expands at the 

 antapex in a broad suleal notch. In figure 85, plate 8, the body is distended by an ingested 

 Pouchrtia. and the outline is somewhat distorted. Figure HH, 4, gives the appearance of the 

 normal individual. Tlie anterior and posterior flagellar pores open at the anterior and posterior 

 junctions respectively of the girdle and sulcus, lying on opposite faces of the body. 



The nucleus is an ellipsoidal body filled with moniliform chromatin strands. It is located 

 in the anterocentral part of the body. Its axes are about 0.5 and 0.3 transdiameter in length 

 respectively. 



Small club-shaped pusules are present at either or both pores. The cytoplasm is very clear 

 and transparent, without granulations. Scattered irregularly throughout were salmou-piiik 

 globules, evidently containing the same fluid as found in the pusules. The individual shown 

 in figure 85, plate 8, had ingested a Poticltcfia. probably rubfsccns. This was enclosed in a 

 food vacuole and still preserved part of its girdle, the nucleus and ocellus and its rose coloring. 

 The general color of the organism is very dilute rose red, diffused through the cytoplasm. A 

 few granules of rose red were collected near both apices with larger masses of tlie same coloring 

 in the central region. A cyst had been recently formed about the body, only slightly larger 

 than itself and closely following its outlines. 



Dimensions. — Length, 62-69/*; transdiameter, 43-52m; axes of nucleus, 

 20-23/t and 16-18;*. 



Occurrence. — Two individuals were taken Jtdy 12, 1917, with a No. 25 silk 

 net in a haul made 6 miles off La Jolla, California, from 80 meters to the surface 

 and in a surface temperature of 20?5 C. 



Comparisons. — Cochlodinium rosaceum forms one of a relatively large 

 number of species in the G^nnnodiniidae distinguished Ijy rose-red pigment. 

 These are found in G/jDuiodiuiiou, Gi/rodi)iium, as well as in Pouclictia. 



It falls within the subgenus Glyplwdinium, being one of the least specialized 

 members of that group, as shown in the slight ventral excavation of the body. 

 It is the only known member of this subgenus with a red color. 



