40 Echin. 
XIV. ECHI NODERMA. 
shaft), Hymenaster , Anasterias (reduction of skeleton, and 
young stages), Belgicella ; Ludwig (204). 
6. Hydrocoel &c. : — in Anasterias chirophora ; Ludwig (204) 
p. 47. 
7. Vacant. 
8. Digestive System:- Gut and caeca in spp. of Mimaster , 
C heir aster, Anasterias , Belgicella ; Ludwig (204). 
9. Vacant. 
10. Mesodermal tissues (exc. skeletal): — Muscles in Cheiraster ; 
Ludwig (204) p. 18. 
11. Vacant. 
12. Genital organs : — in spp. of Mimaster , Cheiraster , Hymenaster , 
Anasterias , Belgicella ; Ludwig (204). 
e. OP HI U ROIDEA . 
f-^. Vacant. 
5. Skeletal Anatomy : — Structure of mouth-parts and arms in 
Ordovician spp., compared with Aspidosoma and with early 
Ast . ; Jaekel (154). — “ Glas-plattchen” in Ophioscolex; Mor- 
tensen (227) p. 87. 
7. Coelom and other body -cavities : — Aboral lacunae of Astro- 
phyton and relations to genital cord; Russo (280). — Peri- 
oesophageal and intestinal lacunae of Astrophyton ; Russo (281). 
8-10. Vacant. 
11. Ovoid gland: — of Astrophyton , ventral half forms amoebo- 
oytes, dorsal half is a lacunar system; Russo (281). 
12. Genital cord : — not enclosed by aboral lacuna and perihaemal 
space in Astrophyton ; Russo (280). 
f. CRINOIDEA. 
1-Jf. Vacant. 
5. Skeleton : — Arms, uniserial and biserial Br., vide n, f, vii, f ; 
Grabau (109). — Meaning and application of term ‘s3'zygy’ and 
its derivatives (p. 219), covering-plates to arms and pinnules in 
Actinometra (p. 220); Springer (297). — Covering-plates of 
pinnules in Antedon , systematic value; Mortensen (227) p. 65. 
6-12. Vacant. 
g. CYST IDE A. 
Vacant. 
h. BLASTOIDEA. 
1, 2. Vacant. 
3. Homologies : — of spiracles and hydrospires, supposed con- 
nection with aquiferous and genital systems ; Russo (278) : see 
also under a, 3. 
h. Vacant. 
5. Skeletal Anatomy: — General account based chiefly on 
Pentremites sulcatus , P. jlorealis , and P. conoideus\ original 
• 5 BB sometimes found ; homologies of A ; supposed integument 
of ambulacra ; anal tube ; alleged absence of peristomial 
covering-plates ; outer side-plates explained as collapsed ten- 
tacles ; Hambaoh (126) pp. 4-21, pis. i, ii. — Tegmina of 
Pentremites , Schizoblastus, Orophocrinus , Nucleocr ., and other 
structural details; Rowley in Greene (115) pp. 121-125, 128. 
6. Hydrocoel, &c. : — Water-vascular ring and branches in Pen- 
tremites ; Hambaoh (126) pp. 6, 16, pi. ii. 
7, 8. Vacant. 
9. Nervous system :— Canals in Pentremites ; Hambaoh (126) 
pp. 6, 12. 
10, 11. Vacant. 
12. Generative organs and gonads: — genital opening and 
