98 University of California Publications. [ ZooLoGy 
Genus Pyrosoma Peron. 
But one genus in the family, hence generic characters same 
as those of the family. 
Pyrosoma Peron, 1804, p. 437, Pl. 72, and all succeeding writers. 
Pryosoma giganteum Lesueur. Fig. 30. 
Je giganteum Lesueur, 1815, p. 70, Pl. I, figs. 1-15. 
P. giganteum Savigny, 1816, p. 207, Pl. IV, fig. 7, and Pls. XXII 
and XXIII, many figures. 
P. giganteum Keferstein und Ehlers, 1861, pp. 72-77, Pl. XII, figs. 
4,5, 7, and 8. 
P. giganteum Paneeri, 1872, pp. 1-25, Pls. I and II. 
P. giganteum Herdman, 1888, pp. 26-29, Pl. I, figs. 4-21. 
P. giganteum Seeliger, 1895, pp. 61-62, Pls. I and II; Pl. IV, 
figs. 3 and 4. Fig. 30. 
Fig. 30.—Pyrosoma giganteum colony, 4.5 em. long. 
Colony cylindrical. or narrowing slightly toward the closed 
end; quite rigid from the firmness of the test; surface bearing 
prominent test processes, these varying much in number, size and 
form, but on the whole inclined somewhat toward the open end 
of the colony, the atrial orifices of the zooids corresponding to 
the processes being on the more convex side of the processes. 
The processes, as a rule, with an oblique, more or less distinct 
plane, with finely serrate edges at their summits. A velum or 
diaphragm of test shutting off to a variable extent the opening 
of the colony. Measurements of three largest preserved colonies: 
first, length 25 em., greatest thickness near open end 2.5 em.; 
second, length 25 em., greatest thickness 3.5 em.; third, length 
19 em., greatest thickness about middle of length, 3 em.; largest 
colonies observed, measured in life, 60 em. long, 40 em. long, 
and 35 em. long. Thickness of wall of largest colonies about 
6mm. Color varying from an entire absence of pigment and ex- 
treme transparency to livid pink, due to pigment in the oozooids. 
