KOFOID AND SWEZY: UNARMORED DINOFLAGELLATA 401 



P. schwartzi, Chattoii (1914&), pp. 434-437, figs. 1-8; (1914c), pp. 157-194, figs. 1-13. 

 P. schwartzi, West (1916), pp. 54, 55, fig. 39. 

 r. schwartzi, Lebour (19176), p. 198. 



Diagnosis. — Colonial Iwdy composed of 2, 4, 8, or 16 zooids, each Gymno- 

 cli)iii())i'\ike in structure, the length ahoiit 0.44 transdiameters, girdle median, 

 without displacement ; sulcus extending length of body ; surface smooth ; nema- 

 tocysts present; color, green to ros3^ Length of chain of eight zooids, 140/*. 

 Baltic, Mediterranean, North kSea, Atlantic, Pacific off La Jolla, California, 

 June-August. 



Description. — The individual zooids are small, subcireular in cross-section, with a length of 

 0.44 trausdiaraeter. The colony of eight zooids lias a length of about 4.21 transdiameters at the 

 widest part, with the body having a subcylindi'ieal form with broad apices. The proximal and 

 distal zooids are usually slightly smaller than the other zooids. The lines of separation of the 

 different zooids sliow the same constriction found in P. kafoirli. The epicone and hypocone are 

 subequal. The apex of the proximal zooid is broadly rounded, or may be slightly flattened. 

 The antapex of the distal zooid is also broadly rounded and often notched by the distal end of 

 the sulcus. 



The girdle of each zooid is nearly submedian in position. It follows a transverse direction 

 around the body without displacement of its distal end. The furrow has a width of about 0.04 

 transdiameter and is deeply impressed with the excavation having an anterior extension, under- 

 cutting the anterior border aud gradually rounding out to the posterior one. Its borders are 

 smooth. 



The sulcus extends from near the apex to the antapex of the colony as a continuous furrow. 

 Its width is irregular, becoming wider at each junction with the girdles, narrowing to half that 

 widtli in the intercingular areas. At the antapex of the distal zooid it forms a broad, sliallow 

 notch. The anterior flagellar pores are located at the junction of girdles and sulcus, the i)osterior 

 pore slightly posterior to those points. The transverse flagella often have a length equal to that 

 of the girdles. The longitudinal flagella have a length slightly greater than the lengtli of the 

 single zooid. 



The nucleus is a s]iheroidal body filled with moniliform chromatin strands. Its transdiameter 

 is about 0.33 transdiameter of the body. As in P. l-ofoidi. the number of nuclei usually equals 

 half the number of zooids of the colony. 



The plasma is finely granular, and often contains oil globules and minute refractive granules. 

 The nematoeysts vary in number and are not constant in position. Food bodies of varying sizes 

 are common in many of the individuals noted, frequently being huge in size and displacing the 

 contents of the entire body. The color of the cytoplasm varies from a grey green to a rose, though 

 none have been found so deeply colored as those figured by Bergh (18816). 



Di:mexsioxs. — Length of individual zooid, lot^; length of chain of 8 zooids, 

 140/i; transdiameter, 65/*; diameter of nucleus, 20/*; length of nematoeysts, 

 10-20/*. 



Occurrence. — This has been found at La Jolla, California, with P. kofoidi, 

 though not so abundantly, in hauls made from June 27, 1906, from near shore 

 to 7 miles offshore and from the surface in hauls from various depths up to 

 595 meters, and in surface temperatures varying from 20-4 C to 21 ?4 C. In 

 1917 it was found in a few hauls made between June 26 and August 22, both 

 in the surface hauls made at the end of the pier at the Biological Station and 

 in the deeper hauls made from 1 to 11 miles offshore from d(>]»ths u]> to 80 

 meters. 



