1964] 
C o oper — Fossil Tardigrade 
43 
Surprisingly, these specimens which had been liberated from the amber 
are hardly more friable or fragile than the exoskeletal remains of 
insects found in forest litter today. 
In addition to the above, and 27 specimens of uncertain relationship, 
two fossils are of exceptional and general interest: a naked ciliate 
protozoan (Wichterman, 1953) and a tardigrade or “water-bear”. 
The occurrence of aquatic and semiaquatic forms such as these, at 
first thought, may seem implausible at best. Yet Kirchner (1950) 
points out that large numbers of aquatic organisms have been dis- 
covered in Baltic amber in recent years, including Radiolaria, Vol- 
vocales, Cyanophyceae, corals with partially expanded polyps, and so 
on, and suggests that some ambers, at least, may have originated from 
the resin flows of swamp trees akin to cypress rather than to firs and 
pines. If the inclusions of chemawinite represent a swamp fauna, then 
the failure to find ants in the samples so far examined would have 
an explanation, and not require the assumption that they are of a 
more recent origin. 
The water-bear is not to be placed in any known genus. The 
specimen itself lies within a small (6X7X3 mm) piece of deeply 
honey-colored, transparent chemawinite that is partially polished on 
two opposite, not parallel surfaces. Submersion in a bath of crown 
oil (refr. index 1.5 15), with illumination by reflected white light, 
permits its study in right dorso-lateral and left ventrolateral aspects 
at magnifications up to 300 diameters. A combination of transmitted 
and reflected light is sufficient to define the distal two-thirds of the 
claws of at least one of each pair of legs. The refractive index of 
chemawinite spans the range 1-535- 1 -537 (Walker 1934), and so 
the specimen was also studied, and all details checked, in 1, 2 dibromo- 
ethane (refr. index 1.538). Though helpful, the gain in image detail 
was too slight to merit prolonged use of this volatile, extremely toxic 
liquid. The tardigrade is placed in the genus 
Explanation of Plate 6 
Beorn leggi Cooper, figs. 1-5; fig. 6 — juvenile (? hetero) tardigrade (see 
text) . 
Figs. 1, 3 — right aspect of the specimen; figs. 2, 4 — left aspect; fig. 5 — 
legs II and III of fig. 3, enlarged. Scale = 100 microns. Silhouettes 1 and 
2 were photographed by William Legg, and are reproduced from his thesis. 
Figs. 3 and 4 were photographed with the specimen immersed in crown oil, 
illuminated with a combination of reflected and transmitted light, and in 
positions similar, but not identical, to those of 1, 2 and of the text figures. 
None of the photographs have been retouched, but the claws in fig. 5 have 
been given emphasis by “dodging” during enlargement. 
