VoL, 2] Ritter —The Pelagic Tunicata. 95 
Doliolum miilleri Krohn. 
D. milleri Krohn, 1852, p. 58, Pl. II, fig. 4. 
D. nordmanni Krohn, 1852, p. 59, Pl. II, fig. 6. 
Doliolum sp. Gegenbauer, 1856, Pl. XV, fig. 8. 
Doliolum Gen. 3B, Keferstein und Ehlers, 1861, p. 68, Pl. X, fig. 3. 
Doliolum miilleri Grobben, 1882, pp. 55-65, Pl. II, figs. 9 and 10; 
Pl. II, figs. 14, 15, 16, 17; and 18; Pl. IV, figs. 21 and 22. 
Doliolum miilleri Uljanin, 1884, pp. 127-130, many figures of ana- 
tomical and developmental detail, and in addition the fol- 
lowing of special importance for identification: Pl. 4, figs. 
1, 3) 4,nand_ 9, larvees Ply, fig. 11; PL 8, fig. 10; Pl. 9, 
fos Pl ti; ho 9: Pil 12) fess 2.3. and, 4. 
This is the least common of the three species of Doliolum thus 
far observed in our area. Hardly more than a dozen specimens 
all told have been taken. These have all been oozooids, and as 
only a portion of them were still in possession of their internal 
organs, my material for study has been scant. Since, however, 
the other generations are sure to turn up some time, as collecting 
goes on, I give the diagnosis of all the generations, relying on 
Uljanin, the most recent writer, chiefly, for all the generations 
except the oozooid, this bemg made mainly from my own obser- 
vations. 
(a) Gonozooid.—Lengeth about 3.5 mm., sometimes reaching 
4 mm.; mantel soft and sticky, in consequence of which surface 
is always covered with foreign particles; muscle bands extremely 
small; gill membrane extending from above opposite the fifth 
muscle band downward and forward into fourth intermuscular 
space; pierced by from ten to twelve branchial stigmata. Endo- 
style extending from slightly in front of third muscle band to 
a little in front of the fifth band. Intestinal tract U-shaped, 
esophageal opening near the center of the branchial membrane, 
the entire loop being situated in the fifth intermusecular space. 
Testes pear-shaped, in fully developed state thrusting out the 
body wall into a hillock; situated alongside the intestinal tract. 
Ovary close behind the testes, containing but very few ova; ova 
maturing earlier than the sperm. 
Color markings: Intestine violet or rose; orange red pigment 
spots on the edge of both branchial and atrial orifices. 
