KOFOID AND SWEZY: UNARMORED DINOFLAGELLATA 331 



The girdle is slightly premedian in position, its proximal end joining the snleus at a distance 

 from the apex of 0.36 and its distal end 0.56 of the total length of the body. It sweeps around 

 the body in a nearly transverse direction for 1 .5 transdiameters before it is deflected posteriorly 

 at an angle of about 35° with the transverse plane, meeting the girdle with a displacement of 

 0.44 transdiameter. The furrow is rather narrow, its width being about 0.04 transdiameter, it 

 is deeply impressed with the concavity undercutting the anterior lip and gradually curving out 

 at the posterior one. The sulcus begins near the apex and passes posteriorly in a sinuous line 

 to near the antapex. Its width is slightly greater than that of the girdle and it is relatively 

 deep, fading out near botli apices. The anterior flagellar pore opens in the sulcus just anterior 

 to its proximal junction with the girdle, the posterior pore at the posterior junction. 



The nucleus is a rather large ellipsoidal body, located anterocentrally. Moniliform chromatin 

 strands follow diagonally across its longer axis. Its major and minor axes are 0.7 and 0.2 

 transdiameter in length respectively. 



The cytoplasm is finely granular, clear and transparent, greenish yellow in color, and usually 

 free from cell inclusions, such as food bodies. The surface is striate with blue-green striae of 

 short dashes arranged in linear series. There are about twice as many of these on the 

 hypocone as on the epicone, where there are about 24 across the ventral face. Our figure (DD, 18) 

 inadequately portrays this contrast. At the antapex is a mass of coral-red pigment occupying 

 the club-shaped projection of the body and extending more or less into the lower part of the 

 hypocone. 



DiiMENSiONS. — Length, 93/^ ; transdiameter, 43/^ ; axes of niiclens, 28f* and 22/^. 



OccrRRENCE. — This was taken Jnly 17, 1906, with a No. 8 silk net, in a 

 surface haul 1.5 miles off La Jolla, California, in a surface temperature of 

 21-9 C. It was quite alnmdant in the hauls made between July 27 and August 

 21, 1917, in both surface and deeper hauls. The number of individuals noted 

 in a short examination ranged from one to seventeen in a single catch. 



CoMPARisoxs. — This species affords the most striking example of the antap- 

 ieal location of its pigment, the entire amount present in the body being here 

 concentrated in the antapex. The more common condition among the pigmented 

 species of Gijrodunum is the presence of pigment in the anterior part of the 

 body, with a scant amount, if any, in the antapieal region, as in G. maruJafion 

 (pi. 6, fig. 62). In G. postmaculatum (pi. 6, fig. 64) an intermediate condition 

 is shown, with a localized antapieal pigment mass and also pigment diffused 

 throughout the loeriphery. G. rnhricandatum leads onwards to the greater 

 development of the same tendency in Pnvillardia (pi. 10, fig. 114), where thei-e 

 is localization of the pigment in the mobile posterior tentacle. 



Gyrodinium schuetti Lenunermanu 



Text figure DD, 5 



Gynvwdhiiuni cornuivni Schiitt (lSt)5), ]>. 113, pi. 22, fig. 71. 

 Spirodinium schuctii, Lemiuerniann (1899), ]). 359. 



Diagnosis. — A large species with broadly ellipsoidal body, its length 1.95 

 transdiameters; girdle a descending left spiral, displaced 0.83 transdiameter; 

 sulcus extending from near apex to antapex; surface finely striate. Length, 

 117/'. Atlantic '( '?) or Bay of Naples. 



