110 THE VOYAGE OF H.M.S. CHALLENGER. 
a less extent. The ovaries of the Pentacrinid are likewise long and fusiform, some of 
them appearing to present somewhat anomalous characters. For in some sections which 
were made for Sir Wyville Thomson by Dr. Stirling, the ovary appears in the arm, 
occupying the usual position between the subtentacular and the ccelac canals where the 
sterile genital cord is normally found. This is also the case in the lower parts of the 
arms of Holopus (Pl. Ve. fig. 2, ov), but I have not yet succeeded in discovering which 
species of Pentacrinus or Metacrinus is distinguished by this peculiarity; for the sections 
above mentioned were not labelled with any name or reference number. I have cut 
sections of the arms of all the more common Pentacrinide, but in none of them have I 
found any such departure from the type of the ordinary Antedon as is presented by the 
ovaries of this unknown species. 
Many years since it was discovered by Prof. Semper,’ during his residence in the 
Philippine Islands, that the ovaries of Actinometra parvicirra (= Actinometra armata, 
Semper, M. 8.) are not attached to the genital cord by their ends in the usual way. For 
a backward process is given off at the point where the short branch of the sterile genital 
cord expands into the fertile portion of the gland ; and it lies within the ventral perisome 
of the arm on the proximal side of the pinnule attachment. This is as fertile as the 
rest of the gland which is actually within the pinnule, so that the whole structure 
appears to be attached to the genital cord at some little distance from its end; and it 
comes right down into the arm at the sides of the subtentacular and cceliac canals, being 
attached almost directly to the genital cord (the so-called rachis), the lateral branches of 
which are quite short. In most sections of the arms, therefore, an ovary is to be seen on 
either side of the central genital cord (Pl. LXI. fig. 3). 
This condition also occurs in Metacrinus angulatus, and in other Philippine 
Comatule, e.g., Actinometra nobilis and Actinometra dissimilis;* and so far as one can 
judge from the appearance of the ventral perisome, without cutting sections, I suspect 
that it is tolerably common in the larger tropical Comatule. 
Although I have examined the ovarian pinnules of a large number of species, I have 
never met with definite openings for the discharge of the ova; and I must therefore, 
like Ludwig, leave undecided the question of the origin of the relatively large openings 
which occur on the inner side of the pinnules of Antedon rosacea at the time of 
sexual maturity. On the other hand, I have found male individuals in which the 
testicular openings are evident enough (Pl. LIV. fig. 3). In Antedon acoela and Antedon 
angusticalyx, for example, the fertile part of the gland is short, thick, and rounded. It 
only extends over four or five of the pinnule segments, and is protected by the tolerably 
regular pavement of plates already described. At about the middle of its length one or 
two small conical projections rise from it towards the ventral surface of the pinnule, and 
1 Arb. zool.-zootom. Inst. Wiirzburg., loc. cit., fig. 1, p. 261. 
2 The specific formula of this type is—a.3. oe 3.3. = 
be 
