1896. ] NEW YORK ACADEMY OF SCIENCES. 247 
Fic. 11. <A. Acadicus var. declivis. a. head shield. 06, pygidium. 
Mag. +. ec, larval pygidium showing embryonic features. Mag. 4°. d, 
adult pygidium in the rachis of which are six somites. Mag. 7. AJl from 
- Div. 1 d', St. Martin’s, N. B. See p. 219. 
PLATE XVI., AGNOSTUS. 
Fic. 1. Agnostus regulus. a, head shield. 6, a joint of the thorax. e, 
Pygidium. Mag. ¢. From Div. 1 ¢?. See p. 213. 
Fic. 2. Agnostus rex Barr. var. transectus n. var. Pygidium, Mag. #¢. 
From Div. 1 d!, St. Martin’s. Seep. 214. 
FIG. 3. Agnostus parvifrons Linrs. var. tessella. a, head shield. 06, thorax. 
¢, pygidium, Mag. #. From Div. 1 d', St. Martin’s, N. B. See p. 221. 
Fic. 4. Agnostus umbo. a, head shield. 6, pygidium. Mag., ¢. From 
Div. 1 d', St. Martin’s N. B. Seep. 222. 
Fic. 5. Agnostus obtusilobus. Mag. ?. From Div. 1 d'. St. Martin’s 
N. B. See p: 223: 
Fic. 6. Agnostus Davidis, Hicks. Pygidium. Mag. ?. From Div. 1 d@’, 
Manuel Brook, Newfoundland. See p. 225. 
Fic. 7. Agnostus gibbus, Linrs. var. partitus. Head shield. Mag. #. 
From Div. 1 c*, St. Martin’s, N. B. See p. 227. 
Fie. 8. A. gibbus var. acutilobus. Mag. 2. From Div. 1d!, St. Mar- 
tin’s, N. B. See p. 227. 
Fic. 9. Agnostus Nathorsti, Brogg, var. confluens, n. var. «a, head shield. 
b, pygidium. Mag. ¢. From Div. 1 d!, St. Martin’s, N. B. See p. 230. 
Fic. 10. Agnostus fissus, Lundgr. var. trifissus, n. var. Mag. ¢. From 
Div. 1 d!, St. Martin’s, N. B. Seep. 231. 
Fic. 11. Agnostus punctuosus, Ang. a, head shield. 06, pygidium. 
Mag. #. From Div. 1 d*, Highland Cove, Newfoundland. See p. 232. 
PLATE XVII., AGNOSTUS AND MICRODISCUS. 
Fig. 1. Agnostus levigatus, Dalm., var. terranovicus, n. var. a, head 
shield. 6, pygidium. Mag. +. From Div. 1 d?, Highland Coye, New- 
foundland. See p. 233. 
Fia. 2. A. levigatus var. mammilla, n. var. a, head shield. b, pygidium. 
Mag. +. From Div. 1 d?, Highland Cove, Newfoundland. See p. 235. 
Fic. 3. A. levigatus var. ciceroides, n. var. a, head shield. b, pygidium. 
Mag. +. Found with the preceding. See p 234. 
Fic. 4. Microdiscus Schucherti n. sp. a, head shield. 0, pygidium. 
Mag. +. From Olenellus limestone, Troy, N. Y. See p. 238. 
Fic. 5. Microdiseus Dawsoni, Hartt. a, head shield. 6, same in profile. 
c, pygidium. Mag. #. d, young larval stage, head shield. Mag. 12. 
e, next larval stage, head shield. Mag. 7°. All from Div. 1 c!, St. John, 
N. B. See p. 240. 
Fic. 6. Microdiseus speciosus, Ford. head shield. Mag. #. From 
Olenellus limestone, Troy, N. Y., figured for comparison. See p. 236. 
Fic. 7. Microdiscus precursor. Head shield. Mag. ?. From Div. 1 c?, 
St. Martin’s, N. B. See p. 239. 
Fia. 8. Mierodiscus pulchellus Hartt. a, head shield. 6, same in profile. 
c, pygidium. Mag. +. d, embryonic or Protaspis stage. Mag. 4°. 
e, early larval stage. jf, pygidium of same. Both Mag. 7°. All from Div. 
1d', St. Martin’s, N. B. See p. 242. 
