75 
pinnules have the character of oral pinnules; from the third tent- 
acles are developed, but none of pinnules preserved carry genital 
organs. — The posterior arm of the same radius has also both 
the first pinnules transformed. That on the outer side has devel¬ 
oped into a small, but true arm, the pinnules beginning on the 8th 
joint. The point is broken; the part left carries three pinnules on 
each side, the second of them having the tentacles developed. The 
first pinnule of the inner side of the arm has developed into a 
true arm, larger than that of the outer pinnule, but distinctly more 
siender than the main arm. The pinnules begin on the 4th joint. 
The point is broken; the preserved part carries 5 pinnules on each 
side, the lower ones of which are developed as oral pinnules. 
In the right posterior radius the oral pinnules of the anterior 
arm are normal, while the first pinnule on the inner side of the 
posterior arm is developed into a small arm, the first pinnule being 
found on the 8th joint. The point is broken; the preserved part 
carries four pinnules on each side, the first of them being devel¬ 
oped as an oral pinnule. 
In the left posterior radius both arms have both their first pin¬ 
nules transformed into arms. On the posterior arm the first pin¬ 
nule of the outer side forms a small, siender arm (Fig. 6, d.), the 
first pinnule being found on the 8th joint; after this follow two 
joints without pinnule, then four joints carrying pinnules placed 
regularly alternating, again a joint without a pinnule and then a 
joint carrying a pinnule, the arm finally ending in a pinnule-like 
point provided with tentacles as the other pinnules. The first pin¬ 
nule on the inner side of this arm has developed into a large 
arm, very nearly as strong as the main arm (Fig. 6, b.). The five 
proximal joints have the character of true pinnule joints; the 6th 
carries a pinnule on the distal side, then follows a joint without 
a pinnule and the 8th joint again carries a pinnule on the distal 
side. From here the joints have the character of true armjoints, 
even forming syzygies (the 9 — lOth, the 16 17th joint and then 
every third joint), and carrying pinnules in the normal way. The 
point is broken, the preserved part carrying eight pinnules on each 
side, not counting that on the 6th joint. The lower one on ea<*h 
side has the character of an oral pinnule, although not very pro- 
nounced. None of the pinnules carry genital organs 
