182 MEMOIRS OP THE UNIVERSITY OP CALIPORNIA 



The micleiis is ellipsoidal and is situated in the posterior part of the body. It is filled with 

 chromatin strands which traverse its longer axis. Its major and minor axes are about 0.62 and 

 0.43 transdiameters respectively in length. 



The surface is sparsely covered with longitudinal striae, about ten across the ventral face, 

 apparently equal in number on the epicene and bypocone. The organism is stated by Lebour 

 (1917&) to be perfectly colorless and transparent. 



Dimensions. — Length, 78/^ ; transdiameter, 48/^ ; axes of nueleus, 32 and 21m. 



OccuBBENCE. — A single individual was seen by Lebonr (1917/;) July, 1915, 

 in a haul made in Phanouth Sound, England. 



CoMPAEisoNS. — It falls within the sitl)genus Lincadhiium by reason of its 

 thin periplast and striate surface in the group including also G. puniceum 

 sp. nor. (fig. Z, 5) and G. irilczeki Pouchet, species with rotund body and sparse 

 striae. Its girdle displacement separates it from G. puniceiim and its small 

 epicone from G. wilczcM.. This form reseml^les G. ahhreviafum somewhat 

 closely, yet differs from it in its lack of a thick ectoplasm, in its fewer striae, 

 and in its slightly different proportions. 



Gymnodinium adriaticum (Schmarda) Kofoid and Swezy 



Peridinium adriaticum Schmarda (1846), pp. 19, 36, 62, pi. 2, figs. 1, 1-5; (1847), p. 12. 



Heteraulacus adriaticum, Diesing (1850), p. 100. 



Heteroaulax adriatica, Diesing (1866), p. 95. 



Peridinium adriaticum, Stein (1878), p. 72. 



P. adriaticum, Maggi (1880a), p. 14; (1880&), pp. 314, 326. 



P. adriaticum, Imhof (1886), p. 101. 



Not Peridinium adriaticum Broch (1910), pp. 179, 191-193, fig. 8. 



Diagnosis. — Body stout, ellipsoidal with hemispherical apices, its length 1.5 

 transdiameters, widest at the girdle; epicone and hj-pocone subequal; girdle 

 equatorial without displacement or overlap; sulcus straight, slight sulcal notch; 

 ochraceous; length, 30-54/*. Adriatic Sea. 



Description. — The body is very symmetrically ellipsoidal, transverse and dorsoventral diam- 

 eters equal; its length 1.43-1.54 transdiameters, widest at the girdle, which is equatorial in 

 location. The epicone and hypocone are subequal, each a little more than a hemisphere by 

 elongation near the girdle, apex rounded, antapex with broad shallow sulcal notch. The girdle 

 is transverse, without deflection or overlap, and the sulcus is confined to the hypocone. The 

 transverse flagellum encircles the body, while the longitudinal one projects 0.8 of the length of 

 the body behind the postmargin, but the origin of the flagella is not shown. 



The nucleus is subeentral, to the left and posterior to the girdle. It is spheroidal, 0.23 trans- 

 diameter in diameter. Cytoplasm with numerous small spherules. Color ochraceous. 



Dimensions. — Length, 35-54/*; transdiameter, 30-35/*, rarely 21-45/*. 



OccuEEENCE. — Described by Schmarda (1846) as very abundant in salt pools 

 of St. Servola on the northern coast of the Adriatic Sea, and as rare in ponds 

 filled by sea water from the inner Venetian lagoons, but abundant in a similar 

 pool at the Forts of the Lido at Venice. It was not found by Imhof (1886), 

 who examined the plankton in Venetian lagoons, and, though cited in literature, 

 has not been reported since its discovery by Schmarda. 



