no. 5 



TERTIARY ECHINOIDS FROM FLORIDA — KIER 



17 



in same specimen ; in larger specimens doubling of adradial secondary 

 tubercles usually in alternate plates. 



Peristome. — Larger, varying from 31 to 34 percent (average 32) 

 of diameter of test; gill slits well developed, curving toward medial 

 line of interambulacra. 



Comparison with the nominate subspecies. — This subspecies is 

 identical in all its characters with the nominate subspecies except 

 in the number and arrangement of the secondary tubercles in the 

 ambulacra and the lateral distance between the primary ambulacral 



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g 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 60 



LENGTH IN MILLIMETERS 



Fig. 10 — Lytechinus variegatus (Leske). Number of large secondary tubercles 

 in each ambulacrum relative to the length of the specimens in the Recent L. varie- 

 gatas variegatus (Leske) and in the Caloosahatchee and Tamiami L. variegatus 

 plurituberculalus Kier, new subspecies. 



tubercles. In the nominate subspecies the secondary tubercles are 

 usually irregularly arranged, alternating from either side of the 

 median suture (pi. 2, fig. 3). In L. variegatus plurituberculaius, 

 however, the secondary tubercles are in two regular series (text 

 fig. 8; pi. 2, fig. 2). Furthermore, they are much more numerous 

 (see scatter diagram, text fig. 10) than in the nominate subspecies. 

 I have found only one specimen out of 59 studied of the nominate 

 subspecies that had a double series of tubercles. Mortensen (1943, 

 p. 440) reports that specimens with a double series of secondary 

 tubercles are rare. 



The lateral distance between the primary tubercles of the same 

 ambulacrum is usually greater in L. variegatus plurituberculaius than 

 in the nominate subspecies. In the five Caloosahatchee specimens in 



