96 THREE CRUISES OF THE “BLAKE.” 
other sea-urchins; they are probably modified pedicellaria. 
The test of Asthenosoma is of a deep claret-color. Phormo- 
soma placenta, another of the modern Echinothuriz (Fig. 360), 
is grayish, or sometimes of a deep brick-color or a yellowish 
orange. The coronal plates of both zones, although they appear 
at first glance similar in structure to those of the regular sea- 
urchins, yet are frequently split up into four distinct plates, as 
in the paleozoic Archeocidaris and the like. 
In a type recalling the Cidaride and the Diadematide, Aspi- 
dodiadema antillarum (Fig. 361), remarkable and interesting 
pedicellarie are found scattered over the whole of the abac- 
tinal part of the test. These may be called sheathed pedicel- 
larıe. The shaft con- 
\ sists of a long, slender 
| radiole, distinctly ar- 
ticulated, surrounded 
by a huge fleshy 
sheath, swelling out 
into three large bags 
on the sides. (Fig. 
362.) The sheath 
Fig. 362, — Aspidodiadema an- 
Fig. 361. — Aspidodiadema antillarum. 3. tillarum, magnified pedicellaria. 
expands at the extremity into a three-lobed cupuliform tip. 
These pedicellarie recall the remarkable sheathed secondary 
spines of Asthenosoma, and form an additional link in the chain 
