38 



STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES 



as the plate patterns of these two species exhibit sub- 

 generic differences. 



Ceratocorys Is probably a very old genus, a conclu- 

 sion suggested by the clear-cut definition of its species 

 along divergent lines, and by the high degree of con- 

 stancy of the species. Ceratocorys hor r Ida and C . ar ma - 

 ta are the most variable units. It should be noted, how- 

 ever, that their variations are not in the nature of tran- 

 sitions toward the other species of the genus. 



Artificial Key to the Species of Ceratocorys 



A. Prominent dorsal and ventral spines present as well 

 as antapical spines B 



A. Prominent spines developed only on the antapical 

 plate C 



B. Small rotund species, diameter 28-55 microns . . 

 C. gourretii 



B. Large angular species, diameter 43-92 microns . . 

 C. hor r Ida 



C. Hypotheca greatly compressed laterally toward the 

 antapex, angle /3 usually greater than 22° ... D 



C. Hypotheca not greatly compressed laterally toward 

 the antapex, angle d less than 22° F 



D. Antapex projected into 2 lobes, antapical spines 2 . 

 C. bipes 



D. Antapex not projected into 2 lobes, antapical spines 



3 or 4 E 



E. Surface pitted, J/d ratio usually greater than 1.00 . 

 C. armata 



E. Surface coarsely and heavily reticulated, J/d ratio 

 less than 1.00 C. reticulata 



F. Antapical spines 4, postcingular 1 clearly visible in 

 ventral view C. aultii 



F. Antapical spines 3, postcingular 1 scarcely or not at 

 all visible in ventral view .... C. skogsbergii 



Subgenus EUCERATOCORYS n.subgen. 



Sulcal plates five; postcingulars six. First postcin- 

 gular plate clearly evident in ventral view without dis- 

 section, overhangs flagellar pore. Type species: C. 

 horrida Stein. 



Ceratocorys horrida Stein 

 (Figures 47-50) 



Ceratocorys horrida Stein, 1883, p. 20, pi. 6, figs. 4-11. 

 Schutf, 1895, pi. 6, figs. 25 (1), 25 (2). Murray and 

 Whitting, 1899, in part, p. 329, pi. 30, fig. 5b. Oka- 

 mura, 1907, pi. 4, fig. 25a-c. Kofoid, 1910, pp. 180- 

 181. JSrgensen, 1911b, p. 146. Forti, 1922, p. 78, 

 fig. 73. Lindemann, 1925, pp. 99-101, figs. 13-19. 

 Mangin, 1926 (1922), p. 71. Dangeard, 1927c, pp. 

 342-343, figs. 7a, 8a-c. Issel, 1928, p. 273. Pavll- 

 lard, 1916, p. 24, PavlUard, 1931, pp. 100-101, pi. 

 3, figs. 17A, 17B. Paulsen, 1931, p. 35. Matzenau- 

 er, 1933, p. 452, figs. 20a-20c. 



Dinophysls jourdanl Gourret, 1883, p. 79, pi. 3, fig. 55. 



? Ce ratochorris trldentata Daday, 1888, p. 103, pi. 3, 



fig. 3. 

 Ceratocorys horrida var. longlcornls Lemmermann, 



IMS, p. 356, 371. 



Ceratocorys horrida forma trldentata Entz, 1902, p. 139, 



— ^rst. 



Ceratocorys horrida var. africana Karsten, 1907, p. 419, 



— Trrs^TTigirr^. 



Ceratocorys horrida var. extensa Pavillard, 1931, p'. 101. 



Matzenauer, 1933, pp. 452, 497, fig. 20d. 

 ? Ceratocorys hirsuta Matzenauer, 1933, p. 453, fig. 23. 

 Peridinium globulus I lapsus pennae], Lindemann, 1925. 



p. 99. 



Dimensions . Length of body Q) 69 (38-97) microns. 

 Diameter of body at girdle in ventral view (d) 67 (43-92) 

 microns. Greatest diameter of body in this view usually 

 just posterior to girdle. Eighty-four specimens meas- 

 ured. 



Shape . Body usually longer than broad. The J/d 

 ratio is 1.07 (0.87-1.35). Epitheca low, dome-shaped. 

 The e/l_ ratio is 0.24 (0.14-0.31). In apical or antapical 

 view, body squarish to circular at girdle. Girdle dis- 

 placed about 1 girdle width. Hypotheca very angular, 

 four -sided, usually somewhat constricted in the middle. 

 Antapex broad, sometimes nearly as broad as girdle 

 region, making sides almost parallel. Body longer on 

 left side than on right (fig. 47B). Posteroventral shear- 

 ing quite marked (fig. 47D, E). The angle 3 was not 

 measured for this species because the lateral edges of 

 the body were not sufficiently straight to allow an accu- 

 rate measurement. 



Plate pattern . Second anterior intercalary narrow 

 and sometimes quite hidden between high lists sur- 

 rounding it, so that its presence can be determined only 

 by dissection. First anterior intercalary may or may 

 not be indicated by lists. Left sulcal plate very small 

 and placed posteriorly, so that the flagellar pore is long 

 and borders the right sulcal plate for half its length. 



Body wall . Thecal wall regularly covered withpro- 

 noimced pits except in intercalary zones. In these zones 

 there is an irregular and variable scattering of pores 

 and, sometimes, pits and ridges. Ventral epithecal pore 

 always present although difficult to demonstrate because 

 it is placed between high lists surrounding second ante- 

 rior intercalary plate. 



Lists. All body lists well developed. Girdle lists 

 very extensive, their width usually exceeding five times 

 the girdle width and sometimes almost half the diame- 

 ter of body. These lists are strengthened by many nar- 

 row irregular ribs, which usually run in from the edge 

 of the list (fig. 47C) but may occur in the center of the 

 list or run out from the body as well (fig. 49B). Poste- 

 rior girdle list usually has fewer of these ribs than the 

 anterior (cf. figs. 47 A, 4C). Girdle transverse lists well 

 developed (fig. 49E). Right sulcal list usually clear of 

 spines. Lists of body spines well developed; those of 

 antapical spines may or may not join with each other. 

 Body lists of epitheca about 0.5 girdle width in height. 

 Those along the sutures of the precingulars run out onto 

 the girdle Ust (fig. 47C). 



Spines . The long brush spines in this species are 

 very striking and characteristic. There are four antap- 

 icals, one dorsal, and one ventral spine. They average 

 about 66 microns in length, or about as long as diame- 

 ter of body, but may attain a length of 120 microns. All 

 spines have "brushes" on their distal half which in 

 some cases, in heavily sculptured individuals, extend to 

 the body (fig. 49B). Structure of brushes described on 

 page 34. 



Reproduction . Fission line typical of genus (p. 34). 

 Since the ventral and dorsal spines are attached to the 

 third and fourth postcingulars, which belong to the left 

 moiety, and since the antapicals belong to the antapical 

 plate, which goes with the right moiety, there is a great 



