432 
CHARLES L. BOULENGER. 
a relation between the arrangements of the two sets of organs 
certainly exists. 
Each of the smaller tentacle-bulbs bears a single sense- 
organ, basally situated near the origin of the velum ; on the 
larger bulbs a second sense-organ is usually developed, 
although occasionally it is missing, just as in a few cases a 
sense-organ may fail to develop on one of the smaller tentacle- 
bulbs (PL 42, fig. 2). 
Text-fig. 1. 
nc 
I 
I 
Part of the umbrella margin of Olindias phospliorica 
(mii lie ri), to show a pair of sense-organs developed at the base 
of one of the primary tentacles, n.r. Nettle-ring. t. Tentacle. 
s.o. Sense-organ, r.c. Radial canal, m.t. Club-shaped marginal 
tentacle. ( x 45.) 
This arrangement of the marginal sense-vesicles recalls 
that which occurs in many species of Olindias, where a pair 
of these structures is to be found at the base of each of the 
primary tentacles (Text-fig. 1). 
The structure of the sense-organs seems identical in every 
respect with that of the similar organs met with in L. tan- 
ganicae, although they appear to be somewhat larger than in 
that species. In this individual there are about thirty tentacles 
