206 
part. The arm-spines are siender and smooth; 1. joint has 4 spines, 
2.—3. joint has 5—6 spines, gradually inereasing in length from 
below, the upper ones l 1 /a times as long as the corresponding 
arm joint; they join in the middle line on the dorsal side (PI. II. 
Fig. 5). The 4th joint has 4 spines, which do not join on the 
dorsal side, the longest (upper) being scarcely as long as the joint. 
The following joints have three and then two short spines, placed 
far down on the side of the joint (Fig 2). The 
inner tentacle pore is small, but distinet, carrying 
a peculiar curved tentacle scale at its outer edge 
(PI. II. Figs. 1, 10). The following pores are very 
small, covered by the single tentacle scale, which is 
elongate and has quite the appearance of being the 
first (lower) arm spine. 
It seems beyond doubt that the animals are 
fullgrown in spite of their small size. Among the 
rather numerous specimens there are none which 
surpass 2 mm. in diameter of disk; however, most 
of thern contain ripe sexual products. These facts 
naturally lead to the conclusion that the specimens 
are fullgrown. This is then one of the smallest 
joints of Micro- Qphiurids made known as yet—if not the smallest. 
phiura; from r ^ 
the ventral side. Jt is true that the Ophiophthirius actinornetræ des- 
The double 
vertebræ are cribed by Doderlein 1 ) is still smaller, having a 
ihe side-plates. diameter of disk of only 0.8 mm.; but there is no 
55 / 
11 • proof that the specimens examined were fullgrown, 
and Doderlein also suggests that they possibly are only young 
stages. 
Regarding the inner anatomy of the animal I would point out 
that there is only a single pair of comparatively large genital 
organs in each interradial space. Bursæ are wholly w an ting; 
the genital products therefore must probably be delivered through 
A pair of the 
outer arm- 
*) Uber einige epizoisch lebende Ophiuriden. In Semon’s Forschungs- 
reisen. V. Jen. Denkschr. VIII. 1898 p. 486. 
