ORTMANN : TERTIARY INVERTEBRATES. 
55 
Fam. CL YPEAS TRIDEE Ag. 
Gen. SCUTELLA Lmck. 
4. SCUTELLA PATAGONENSIS DeSOr. 
PI. XI, Fig. 4T*. 
1846 Scutella patagonensis Desor, in : Bull. Soc. geol. France, ser. 2,v. 4, 287. 
1846 Echinarachnms juliensis Desor, ibid. 
1847 Scut. pat. and Ech. jut. Agassiz and Desor, in: Ann. Sci. nat. ser. 
3, V. 6, p. 135 and 134. 
1858 Scut. pat. and Ech. jut. Desor, Synops. Ech. foss., p. 234 and 231. 
1897 Scut. pat. and Ech. jut. v. Ihering, in: Rev. Mus. Paul., v. 2, p. 337 
and 336. 
1898 I her in gi a patagonensis Lahille, in : Rev. Mus. La Plata, v. 8, p. 437, 
pi. 1 and 2. 
Test depressed, margin thin. Outline circular, oval, subpentagonal, or 
more or less transversely dilated (alate), sometimes almost semi-circular, 
with the posterior margin truncated. Margins often undulated and the 
posterior one with a more or less distinct median incision. Apex sub- 
central. Ambulacral petals of uniform size, lanceolate, more or less open, 
sometimes lyrate, with a few scattered pores diverging from the extrem- 
ity of the petals. Interambulacral plates of upper side increasing in width 
from the apical system to near the end of the petals ; then they decrease 
suddenly in width, so that the interambulacral space narrows considerably 
toward the periphery. On the periphery the interambulacral space is con- 
siderably less broad than the ambulacral space. Ambulacral furrows of 
lower side dividing into two branches at a short distance from the mouth, 
each branch subdividing again near the periphery of the test into 2 to 4 
branchlets. Anus submarginal, distant from the posterior edge of the test 
about 1-2 times its diameter (in young individuals it is marginal, with a 
slight inclination toward the lower surface). 
Diameter of largest complete individual of rounded form : 62 mm; of 
a fragment: 70 mm; alate form: longitudinal diameter: 76, transverse 
diameter, 94 mm. 
Remarks: The two forms of Scutellids, described as two different spe- 
cies belonging to the genera Echinarachnms and Scutella respectively, 
