VoL. 2] Ritter.—The Pelagic Tunicata. 91 
to ehrenbergu or miilleri, as comparison with published descrip- 
tions of the trophozooids of these species shows. D. tritonis being 
the only other species known to occur in the area, and at the 
same time the most abundant of all the species, would be the 
one to which it would seem most likely to belong. The large 
size of the zooids and the length of the dorsal process, as inti- 
mated by the fragment secured, tends to support the same con- 
clusion. 
D. tritons is the most abundant, as it is the, largest, spe- 
cies in the area. The gono- and phoro- zooids were taken in 
great abundance at San Diego in May and June of 1904. The 
giant oozooids, which I have supposed to belong to this species, 
occurred in particularly large numbers at Avalon in July, 1901. 
The gonozooids and oozooids have also been taken, though in 
less quantity, in March, October, and November. 
Doliolum Ehrenbergii Uljanin (not Krohn). 
Doliolum Gegenbauer, 1856, Pl. XVI, figs. 12 (?) and 13 (2), 
and fig. 15. 
Doliolum Gen. 2B and 4B, Keferstein und Ehlers, 1861, p. 68, Pl. 
IX, figs. 5 and 7; and Pl. X, fig. 4. 
Doliolum denticulatum Grobben, 1882, pp. 23-41, Pl.1, figs. 3, 4, 
and 5; Pl. 2, figs. 7 and 8. 
Doliolum ehrenbergii Uljanin, 1884, pp. 132-133, Pl. 5, figs. 1 and 
3; Pl. 12, fig. 8. (Numerous other figures are assigned to 
. ehrenbergu, but I here refer to only those that undoubt- 
edly represent the species as here understood.) 
Doliolum ehrenbergii Herdman, 1886, p. 46, Pl. III, figs. 5 and 7. 
Doliolum ehrenbergii Lahille, 1890, p. 65, figs. 47, 48, 49, and 50. 
(a) Gonozooid. Unknown. 
he g 0 
Fig. 27.—D. ehrenbergii, 00z001d, before loss of internal organs. 
(b) Oozooid—Fig. 27. Leneth from .925 mm. to 2.77 mm., 
between disappearance of larval characters and beginning of 
