Vol. 3] Kofoid. — Dinoflagellata — New Species. 315 



large, laterally compressed, posteriorly located nucleus and a few 

 irregular pale cliromatopliores in the hyaline plasma. 



Differs from D. acuta, D. sacculus and D. rotiindata in its 

 symmetrically ellipsoidal body and very hyaline aspect. 



Length, excluding collar, 43/a; dorso-ventral diameter exclud- 

 ing fin, 25/^. 



Rare in neritic plankton off San Diego in midsummer. 



Amphisolenia spinulosa, sp. no v. 



PI. 32, figs. 53-55. 



A large species related to A. palmata Stein but without ter- 

 minal expansion of the antapical horn and with no lateral spinule. 



The body is elongated, its total length about 40 times the 

 greatest dorso-ventral diameter of the midbody. Neck and head, 

 midbody and antapical horn forming respectively 0.1, 0.3, and 

 0.6 of the total length. The head is depressed, with convex upper 

 and under surface, and impressed furrow. It is oblique (30°) 

 to the main axis. The neck is of nearly uniform calibre, and is 

 channeled ventrally as it approaches the flagellar pore. The mid- 

 body is elongated, fusiform, tapering gradually into the long 

 apical horn. This is of a nearly uniform calibre and is deflected 

 distally to the right and ventrally in a curve in its terminal third. 

 It is not expanded distally as in A. palmata but bears a similar 

 group of three, short, equal, divergent, terminal spinules. There 

 is no lateral spinule as in A. palmata. Chromatophores sub- 

 spherical, or irregular. 



Length, 740-800ju,; greatest dorso-ventral diameter, 18-20/x: 

 diameter of antapical horn, 3-5/^. 



Taken in oceanic plankton off San Diego in June and October. 

 Zoological Laboratory, University of California, 



March 31, 1907. 



