1 
170 | 
My material consisted in a large number of the larval and post- | 
larval stages of Asterina gibbosa forming a fairly complete series from | 
larvae in which the larval appendage was still fairly large, up to young | 
starfishes the greater radius of which measured about 2 mm. | 
In my paper on Amphiura squamata I described, three sinuses, È 
associated with the stone-canal, and the adjoining dorsal organ (ovoid | 
gland). Of these c (Fig. 1 a), is situated, ventrally, and mesially (i. e. | 
nearer the mouth), with respect to the stone canal, which opens into | 
it, as does also the pore canal leading to the single madreporic pore; | 
5 on the other hand is situated peripherally and dorsally with respect 
sinus b 
(axtal sinus)... - 
OVOT ONG LC III 
4....stone canal 
(dorsal organ) 
SUBS a na e LEITERN 
(aboral sinus) Y 
genital rachis... (nada 
axial sinus 
of Asterina ) 
- madreporic pore 
to the ovoid gland, and partially enwraps it laterally, whilst @ is a | 
portion of the aboral sinus, whose undulating course dorsal in the 
radii and ventral in the interradii, has been so well described by Lud- 
wig?. Of these sinuses I showed that a, and 6, originated as involu- 
tions of the coelom, whereas c, which communicates with the stone" 
canal, was present in the youngest stages examined by me. I also. 
showed that the ovoid gland itself is derived from a layer of peritoneal — 
cells, and that the genital rachis which is contained in the aboral 
sinus, originates as an outgrowth from the ovoid gland, so that the 
sexual cells are primarily peritoneal. 
2 »Neue Beiträge zur Anatomie der Ophiuriden. Zeitschrift f. wiss. Zoologie. 
34. Bd. 1880. 
