30 
CEETACEOUS ECniNODEEMATA 
CASSiDrLiN.E. Lutkcn, in Ins Memoir on the Echinoiclea in 18G4, states that 
Ccmklulus and Bhynehopygits should prohahly he nnited, as Cass, caribheearnm 
eomhincs characters of both, hut Agassiz subsequently separated that species as 
a distinct genus under the name Jxhyncholampas. 
1. Cassidultjs OLDnAAiiANTJS, StoUczha. PL V, Pigs. 10 — 11. 
Cass, testa late ovata, antice regidariter rotimdata, postice rotundate snJxw- 
gulata atque paido latiore, modice elevata, laterilms convexiuscidis, ad peripheriani 
suhohtitsa, infra planala, circa aperturam paxdidum depressa, supra cequaliter gra- 
nulate tuhercidata, infra crasse tnhercidifera regione niediana longitudinali gra- 
mdifera excepta; apice apertnraqm panlo antice ecceulricis, primo tahidis geni- 
talibus quatuor perforalis et qidnque ocidaribus nmlto minoribns comqwsilo, altera 
lobis quinquehreribits crassis circinndata, extus qdiyllodiis late ovatis allernantibas ; 
q^etalis snbceqnalibus, antico longissimo, dnobus posticis hrevissimis, qnoqne 21 — 27 
p)oros in una serie continente ; regione anali profmde lateqne depressa, ano rotundate 
ovato, spacioso, infra marginern superiorem sito, a terminatione postica fere tertiam 
partem totius longitudinis testes distante. 
Long, speciininis mnximi 33, latit. 27, altit. 15 nun. 
A very characteristic species, notably distinct from all other Cassidnli by a large 
anal depression, while the anus itself is situated near the upper narrower end of 
the vertical portion of the groove, and is of a largely ovate shape. The test is 
moderately and almost uniformly convex above, finely tuherculated, below flat and 
coarsely tuherculated, except along the middle, which is slightly elevated and granu- 
lar, somewhat depressed round the mouth, this last being surrounded by five short hut 
very prominent lobes, alternating with the broadly ovate phyllodia. The petals are 
considerably narrower towards their ends, subcqual ; the anterior impair one is the 
longest, and the two posterior are slightly the shortest ; each has 24 to 27 pores in a 
series, and the outer pores in each are slightly more transversely elongate than the 
inner ; the antero-laterals diverge under an angle of 140°, and the postero-latcrals 
only under an angle of 45°, hut as soon as they have passed the anus, the angle ot 
divergence rapidly changes to 55°, the posterior part of the test being some- 
what broader than the anterior, which at the front is regularly rounded. The 
genital and ocular plates are regularly placed, hut rather difficultly discernible, 
except their pores. 
Locality . — Aorth of Poodoopolliam, in a somewhat ferruginous earthy lime- 
stone ; not common. 
Formation . — Arrialoor group. 
( 100 ) 
