ON 'I'HE DIPLOCHORDA. 493 
EXPLANATION OF PLATE 29, 
Illustrating Dr: A. T. Masterman’s paper “On the Diplo- 
chorda. Part V. Certain Points in the Structure of 
Tornaria.” 
List oF ABBREVIATIONS. 
a. Anus. a.d. Adoral band. 6.p. Buccal pad. ce. Ceelom. ¢.o.a. Ante- 
rior part of circum-oral band. ¢.0.p. Posterior part of cireum-oral band. 
d.c. Dorsal cilia of pharynx. ez. Extra-oral band. g.p. Gastric pad. hy. 
Hydrocele. ix¢. Intestine. m. Mouth. Jy. Lateral groove. ws. sophagus. 
p.a. Peri-anal band. p.c. Pre-oral coelom. pa. Pharynx. pA.d. Dorsal 
chordoid wall of pharynx. pl. Pleurochord. p.v. Proboscis vesicle. sé. 
Stomach. v. Vestibule. v.c. Ventral cilia of pharynx. 
Fies. 1—4.—Selected sections from a frontal series through a Tornaria 
larva. They are the 4th, 7th, 11th, and 16th respectively of the series. 
Fics. 5-9.—The pharyngeal region of the same series, seen with higher 
‘magnification. : 
Fig. 5 is part of Fig. 2, the 7th section of the series. 
Fig. 6 is part of Fig. 3, the 11th section of the series. 
Fig. 7 is from the 18th section of the series. 
Fig. 8 is from the 15th section of the series. 
Fig. 9 is from the 22nd section of the series. 
Fic. 10.—A dorsal view of the entire Tornaria. 
Fic. 11.—Latero-ventral view (left side) of a slightly later stage of Tor- 
naria; more highly magnified. 
Fic. 12.—Lateral view of the pharynx of Tornaria. 
Fic. 18.—A series of optical sections of the opening between stomach and 
intestine of Tornaria, drawn to show consecutive stages in the closure of 
the opening. 
Fic. 14.—Optical section of the stomach and intestine of Tornaria to 
show alimentary currents. 
Fre. 15.—Iateral view of pharynx and stomach of early Tornaria. 
Fie. 16.—Frontal view of the mouth and pharynx of Tornaria. | 
