NO. 5 TERTIARY ECHINOIDS FROM FLORIDA — KIER 43 



there are lunules in all the paired ambulacra. A lunule in ambula- 

 crum III is present in a specimen 35.0 mm long (text fig. 41). 



Comparison with other species. — This species is distinguished from 

 all the other species of the genus in having in adult specimens five 

 instead of four ambulacral lunules. 



Remarks. — Previously all species of the Mellitidae having four 

 genital pores and five ambulacral lunules have been referred to 

 Leodia. Although this species has five ambulacral lunules, it has all 



Fig. 37. — Mellita aclinensis Kier, new species : Adapical view of abnormal 

 specimen U.S.N.M. 648193, from the Tamiami formation, loc. 27, X 3. 



the other characters of Mellita that distinguish this genus from 

 Leodia (see table 4). Therefore it seems reasonable to consider 

 this a species of Mellita, and to broaden the generic concept of the 

 genus to include species having five ambulacral lunules. 



Durham (1961, p. 3) predicted that Mellita would be found in 

 the Miocene and Pliocene of the Neotropical region: "In view of 

 its occurrence only in the tropical and warm temperate areas of the 

 western Atlantic and eastern Pacific, it is evident that Mellita must 

 have a fossil record extending back to at least the upper Miocene 

 when the Central American seaways were open (Durham and Alii- 



