d+ 
EMBRYOLOGICAL MONOGRAPHS. 
12-13. Abnormal Blastule of Holothuria tubulosa. From K. Selenka, Zur Entwickelung dey Holothurien, 1876, 
Pl. XIII. Quoted above. 
14-27. Homologies of Echinoderm Larve. From Johannes Miiller, Ueber den Allgemeinen Plan in der Entwicke- 
A. 
B. 
D 
d. 
d. 
e, el, 
q gf. 
Ls Ls 
M, 
N. 
Ys Y- 
lung der Echinodermen, Pt. VI., 1852, PI. Il. Quoted above. 
Anterior or oral plastron. 
Posterior or anal plastron, in which is placed 0, the anal opening. » 
Intermediate oral area, in which is placed C, the mouth, and a, the anterior, b, the posterior edge of 
the transverse part of the oral vibratile cords ; c, the connecting vibratile cord between the oral 
and anal plastrons. 
Posterior lobe of the vibratile cord of the oral plastron. 
Anterior lobe of the vibratile cord of the anal plastron. 
Arms of the anterior and posterior plastrons on the oral side. 
Arms of the anterior and posterior part of the dorsal vibratile cord. 
Processes forming in Echini arms at the anal extremity, not in the line of the vibratile cord. 
Connected vibratile cord of the dorso-anal system. 
Connected vibratile cord of the oral ventral plastron. 
Brachiolarian appendages of the Starfish larva. The whole of the Brachiolaria of fig. 27, beyond 
the brachiolarian arms, corresponds to the Starfish larval organ, such as has been figured by Sars, 
Thomson, Ludwig, and others. 
16. Shows the development of an Auricularia from the typical Echinodermal larva, fig. 14. 
-19. The development of an Ophiuran Pluteus from the typical Echinodermal larva, fig. 17. 
23. The development of an Echinoid Pluteus from the typical Echinodermal larva, fig. 20. 
4-27. The development of a Starfish Brachiolaria from the typical Echinodermal larva, fig. 24. 
For modifications of the typical form of development of the Holothurians, see Pl. XIV. figs. 13-27, Pl. XV. 
figs. 5-11. 
For modifications of the typical form of development of the Ophiurans, see Pl. III. figs. 1-20, 26-31. 
For modifications of the typical form of development of the Starfishes, see Pl. V. figs. 1-4, 15-49, Pl. VI. 
For modifications of the typical form of development of the Sea-urchins, see Pl. XII. figs. 30-34. 
