PIL AWD Ne: 
SPHENODISCUS. 
Thee, I, Silaqaodhsens Uaoncullenns ((Ow@))——soo5ss cess eco Sse ssnccu SSeS se saeseocessosscosss 
Fig. 1. Suture of paranepionic substage, >< 25. 
2. Details of siphuncle, showing what seemed to be a collar above and a pro- 
longed funnel reaching from the septum to the opening of the collar. 
3. Sutures of the neanic stage, showing the division of the first primitive lat- 
eral into three saddles, first, second, and third of the later stages, and 
the mode of increase of the so-called auxiliary saddles and lobes on the 
line of involution, 5. 
4. Section of the two youngest yolutions observed, >< + 4. 
5. Lateral suture of later but not fully adult stage, 
6. Dorsal suture of same age, 8. 
Rock Creek, Wyoming; Fox Hills group; Coll. Yale University, No. 1697. 
Fics. 7-9. Sphenodiscus lenticularis var. mississippiensis Hyatt _-..-..---..--------------------- 
Fig. 7. Lateral suture, natural size. 
8. Dorsal suture of same age, but one-fifth over the natural size; actual meas- 
urement is 48 mm. instead of 60 mm., the length of the figure. 
9. Lateral suture, natural size, from specimen in Coll. Acad. Nat. Sci. Phila- 
delphia. 
Three miles northeast of Ripley, Miss.; Ripley group; Coll. U. 8. Nat. Mus., 
No. 20863¢. 
ErGe lO Sp enaalescris eea vert eluyrctititey Seat ee eat eee sae reer 
Suture, natural size. Fox Hills group; Coll. Mus. Comp. Zool., Cambridge. 
ATG! SHLD SEs S 1) REMLOCUSCLUSHLO DCLLIOS  (@ANUT C TAN y3) Nepemes ana aoe : 
Fig. 11. Right side. 
12. First three saddles of left side at same age, natural size. 
13. First three saddles of left side of the youngest suture shown on Pl. VII, 
fig. 1, natural size, for comparison with fig. 12. 
Buncombe Hills, Pontotoc County, Miss.; Ripley group; Coll. Frederick Braun, 
Brooklyn, N. Y. 
~I 
~I 
66 
