434 
LIST OF FOSSILS. 
S. BUMASTIPORMIS. EigUs. 
Animal subovate, oblong, very smooth, not serrated. Color olivaceous green; under side, legs, and segmentary mar¬ 
gins, pale ochraceous. Head a transverse square, inserted in a notch of the first abdominal segment. Eyes lateral, 
reniform, closely approximating to the anterior portion of the first segment. Superior antennae slightly longer than the 
head, three-jointed; the basal joint subangular, much enlarged, and soUd; terminating filament composed of numerous 
small and short articulations. Inferior antennae nearly double the length of the upper, four-jointed, and ending with 
numerous short and smaller joints. Abdomen articulated into seven subequal segments, each containing beneath a pair 
of perfect legs. Legs rather stout, each terminated by a strong slightly incurved nail. The segmentary impressed lines 
on the basal segment of the tail do not extend to its lateral edges; the terminating segment is triangular, and entire. 
The swimming fins are much depressed; the superior one extends nearly the length of the segment; the lower one is 
about two-thirds its length, and closes in under the superior one similar to the sticks of a fan. The subcaudal branchial 
laminae are bifid; one portion articulating on the other, not unlike the palpi on the jaw appendages. These laminE are 
eight in number. 
In consequence of the near resemblance of this animal to the fossil genus Bumastus, it has received its specific appella¬ 
tion. When in a state of contraction, it assumes the form of a ball. 
Found in considerable abundance in pools left by the receding tides, along the shores of Cape Horn and its adjacent 
islands. 
