426 MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



posteriorly. Situated somewhat posteriorly is a large food body in wliicli is found a group of 

 radial rodlets radiating out from a common center and occupying apparently the center of the 

 food body. These vary from 8-10;n in length and from 0.5-1/1 in width and are pale greenish 

 in color. The food mass consists of a small Gymnodinium, pale yellow in color. All evidence 

 of internal structure had disappeared, leaving only an ovoidal outline and a broad girdle to 

 distinguish it. 



The color is a pale rose color distributed evenly throughout the cytoplasm near the periphery, 

 leaving the central mass almost colorless. The animal was enclosed in a thin transparent cyst 

 a little larger than the body and conformable to its contour. 



Another encysted form (fig. P, 2), referred to N. partitum because of its ocellus and short 

 rodlike bodies resembling nematocysts, was enclosed in a spheroidal, double-contoured, trans- 

 parent cyst of nearly spherical form. "Wlien first observed it had an inner membrane closely 

 applied to the spherical protoplasmic mass, but this later expanded somewhat irregularly till 

 it met the outer membrane. In addition to the ellipsoidal nucleus and typical ocellus the 

 enclosed protoplasmic sphere contained a yellow food ball and some scattered peg-shaped bodies, 

 interpreted as nematocysts, the largest of which is about the size of the nematocysts of the 

 individual of normal form. 



The presence of cysts and of food balls in both of the individuals of this species that we 

 have seen, and the abnormal (spherical) form of one of these, suggests that these may be 

 digestion cysts, and that the form and contour may be more or less profoundly modified in this 

 state. The individual upon which this description is based was, however, apparently normal in 

 all important details. 



Nutrition is undoubtedly holozoic and other species of Gymnodinioidae CAndently fall victiuLs 

 to the voracity of this marauder. It is obvious that the Gymnodiniion within the food vacuole 

 is so large that its entrance into the cytoplasm of Nematodinium would severely stretch the 

 intereingular part of the sulcus, close to which it lies, when it was ingested. 



Di:mexsioxs. — Length. 91^ ; transdiameter, 52/^ ; diameters of nucleus, 30-35^' 

 and 25 -28m; length of nematocysts, 5-8/^. 



OccuBEENCE. — The individual figured was taken June 20, 1906, at La Jolla, 

 California, with a No. 20 silk net in haul from 37 meters to the surface. 

 Another encysted form was taken on July 9, 1917, with a No. 25 silk net in a 

 haul from 80 meters to the surface in a surface temperature of 19-2 C. 



Co:\jPARisoxs. — This species is a trifle smaller than N. armatum, has more 

 numerous and smaller nematocysts, 5m to 8m as compared with 14m to 22m, and 

 a scattered ocellus instead of a concentrated one. The diffuseness of the ocellus 

 is noteworthy as compared Avith the Pouchetiidae as a whole. No species of 

 the famil}' has more diffuse lenses and few exceed it in the diffuseness of its 

 melanosome. The optical efficiency of the ocellus of this species judged by its 

 position, nmltiplieity of lenses, and lack of coordination of these with the pig- 

 ment must be of a low order. 



Nematodinium torpedo sp. nov. 



riate 11, figure 124; text figure NN, 3 



DiAGXosis. — A large species with elongate fusiform body, its length 2.9 

 transdiameters ; girdle a descending left spiral of 2.25 turns ; sulcus with nearly 

 2 turns, extending almost from apex to antapex; ocellus posteriorly located. 



