FAMILY GONYAULACACEAE 



47 



2 of the 82 specimens measured was this ratio more 

 than 1.00, viz., 1.03 and 1.19. The broadest specimen, 

 with an_l/d ratio of 0.77, on the other hand, was connect- 

 ed with the mean by a continuous series of intergrades. 

 It was at first thought that the smallest specimens rep- 

 resented a distinct species, but when the frequency of 

 the width of all specimens was plotted, a primary mode 

 was found at 65 microns and a secondary one at 45-50 

 microns with so many records between that not even a 

 variety was indicated on this basis. The thickness of 

 the body wall and of the associated lists is variable; 

 forms with extremely heavy thecae are common. 



Reproduction . Stein (1883) figured an individual 

 containing a resting cyst (pi. 7, fig. 2). He also showed 

 an emerging cyst (pi. 7, fig. 9) with the girdle indicated. 

 Other figures by Stein represent cysts with two and four 

 daughter cells (swarm spores?) with girdles (figs. 11, 

 12). Finally, Stein presented (figs. 13-16) specimens 

 which he interpreted as representing stages intermedi- 

 ate between these young daughters and the mature spec- 

 imens. His material was from the Baltic and Atlantic. 

 Schutt (1895, pi. 8, fig. 30, 9, 10) shows daughter cells 

 with half-old and half-new thecae, also a "double spore" 

 (fig. 30, 7). No specimens representing reproductive 

 stages were found in the Carnegie material. 



Distribution . Paulsen (1908) stated that Gonlodoma 

 polyedricum is an Atlantic subtropical species. Lebour 

 (1925) also designated it as subtropical. Both authors 

 record the species as rare in the Gulf Stream. It is, 

 however, a widespread tropical species, as shown by 

 the Carnegie and other observations. It was reported 

 from the tropical Atlantic by Schmidt (1901) and Pavil- 

 lard (1931); from the Baltic by Aurivillins (1896) and 

 Abshagen (1909); from the Mediterranean by Schmidt 

 (1901), Forti (1922), Issel (1928), and Paulsen (1931); 

 from the Pacific by Schmidt (1901); and from the Indian 

 Ocean by Schmidt (1901), and Matzenauer (1933). 



In the Carnegie collection G. polyedricum was found 

 at 148 stations: 30 in the Atlantic and 118 in the Pacific. 

 There are 471 records of occurrence: 280 rare, 178 

 occasional, and 13 common. The species was found less 

 frequently with Increase in depth, with 218 records for 

 the surface, 143 for 50 meters, and 110 for 100 meters. 

 There are 190 pump records and 281 net records. It 

 was found in both hemispheres and in all months of the 

 year. 



The species was found at practically every station 

 In the tropical and subtropical regions, and it strayed 

 beyond these regions much more than did most of the 

 other tropical forms (fig. 61). Thus, it was foimd in the 

 North Atlantic Drift as far as the British Isles (station 

 6c); in the western Pacific north of 40° north; in the 

 eastern Pacific to 37° north; and in the South Pacific to 

 40° south. There was no particular center of abundance. 

 The records of "common" and "occasional" were scat- 

 tered throughout the range. 



The surface temperatures at the stations where the 

 species occurred at any depth varied from 12"4 to 

 29.°5 C. The ranges of hydrographic conditions in situ 

 were as follows: temperature, 10° 6 to 29°. 6 C; salinity, 

 29.7 to 37.1 o/oo;, pH, 7.17 to 8.47; phosphate, 3 to 

 198 mg P04/m3. 



It can be concluded from Carnegie observations that 

 Gonlodoma p olyedricum is a fairly common, widespread, 

 tropical species. It is similar to Ceratocorys horrida 

 In this respect, but it extends into water of lower tem- 

 perature. Thus, it was found near the British Isles 



where the surface temperature was only 12 °4 C; north- 

 east of Japan where the surface temperature was 15 °9; 

 off California, in 16 °2 water; and in the southeastern 

 Pacific, in 15° water. It occurred at 6 stations where 

 the surface temperature was less than 19°. This species 

 should be an excellent plankton indicator, as it is ubiq- 

 uitous in the tropics and seems to survive transfer to 

 cooler regions. It should indicate water masses of 

 tropical origin. 



The species apparently suffers no decrease in wa- 

 ters of low nutrient content. There were 165 records in 

 water with less than 10 mg P04/m3. 



Family GONYAULACACEAE Lindemann 



Diagnosis . "Shape very variable, spherical, angu- 

 lar, elongate, sometimes with hornlike processes or 

 distinct spines at both ends. Girdle about equatorial, 

 often strongly spiraled. Small posterior intercalary 

 present. Length, 18 microns to 167 microns." (Linde- 

 mann, p. 84, 1928.) 



Genus GONYAULAX Diesing 



Diagnosis . "Body variously shaped, spheroidal, 

 polyhedral, broadly fusiform, elongated with stout apical 

 and antapical prolongations, or dorso-ventrally flat- 

 tened. Apex rounded or truncate symmetrically or a- 

 symmetrically, never acutely symmetrically pointed. 

 Antapex rounded, flattened, or pointed symmetrically or 

 asymmetrically. Girdle usually equatorial, descending, 

 displaced dlstally one to seven times its own width, and 

 sometimes with slight overhang. Transverse furrow 

 impressed or not; longitudinal furrow usually slightly 

 indenting the epitheca, often flaring dlstally, well devel- 

 oped, reaching to or approaching the antapex. Thecal 

 wall consisting of one to six apical plates, none to three 

 anterior intercalaries, six precingulars, six girdle 

 plates, six postcing^ulars, one posterior intercalary, and 

 one antapical. The longitudinal furrow occupies the 

 whole of the ventral area which slightly indents the epi- 

 theca and consists of one anterior, about four interme- 

 diate and one posterior plate. The midventral plate of 

 the apical series is usually a narrow plate extending 

 posteriorly to a junction with the anterior plate of the 

 ventral area, thus parting precingulars one and six. 

 When guarded by lateral ridges it simulates an anterior 

 extension of the longitudinal furrow. It bears at its apex 

 a delicate extension, the closing platelet wJiich covers 

 the apical region. 



"Surface smooth or rugose with major thickenings 

 along suture lines and minor ones on plates forming a 

 regiilar or irregular polygonal mesh of varying size, 

 often with vermiculate, longitudinal elements predomi- 

 nating, sometimes spinulate. Furrows with or without 

 lists which in many species are ribbed or spinulate. One 

 or more antapical spines sometimes present, rarely 

 with sheathed spines of the Ceratocorys type. Plates 

 porulate, with pores in centers, angles, or nodes of the 

 mesh. A peculiar large ventral pore occurs to the right 

 of the midventral line usually near the suture between 

 apical one and the plate to its right. Theca divided ob- 

 liquely in fission. Ecdysis frequently seen. Chromato- 

 phores yellow to dark brown, often dense. In fresh, 

 brackish, and marine waters from boreal to tropical 



