Variation of Y 0 would fall between Y c - 1.96 S y x and Y c + 1.96 S y x at the 95% level of 
confidence, where Y is the sixth abdominal segment length (0.05 mm); x is the 
carapace length (0.05 mm); b is the Y intercept; m is the slope of regression line; c is 
the subscript for 'calculated*; o is the subscript for 'observed*; and S y x is the 
standard error of estimate for linear correlation. The sixth abdominal segment was 
greater than 2.65 mm in 92% of the P. aztecus postlarvae, but only in one of the P. 
duorarum postlarvae. All postlarval P. aztecus could be distinguished from P. duorarum 
by averaging the deviation of individuals regressions between 7 pairs of morphometric 
characters: carapace length and sixth abdominal segment length, carapace length and 
rostrum length, carapace length and eyestalk length, carapace length and antennal scale 
length, carapace length and antennal spine length, rostrum length and eyestalk length, 
and antennal scale length and antennal spine length. The individual was assigned to the 
species from whose 7 regression lines showed the least average deviation. The 
calculations for average deviation from regression lines are as follows: 
Y c = b + m X Q 
Y - Y 
c o 
where Z is the deviation from regression line; and Z the average deviation from 
regression lines. The values of b, m and S y x for each species according to the number 
of dorsal rostral spines present are given in the citation. The laboratory reared 
specimens confirmed that the absence of dorsal carina spines on the sixth abdominal 
segment of P. setiferus can be used to segregate it from P. aztecus and P. duorarum 
only if the shrimp has more than 5 dorsal rostral spines. Approximately 49% of the P. 
aztecus had the lateral spine longer than the tip of the antennal scale, and 2% of them 
had the lateral spine equal to the tip of the antennal scale. The third pereiod in 75% of 
all specimens examined in the present study was found to extend beyond the eye. Four 
out of 962 postlarval shrimp from Florida waters were morphometrically similar to P. 
aztecus. The remaining 958 specimens were morphometrically identified as P. 
duorarum. 
1967 - 1968 
Manker, J. P. (1969) Origin and distribution of silicate minerals in a carbonate 
environment, Florida Bay. M. S. Thesis. University of South Florida, Tampa, FL. 49 pp. 
Chlorite, montmorillonite, illite, and kaolinite have been found in the clay-size insoluble 
residue or Recent carbonate sediments of Florida Bay. Clay mineral distributions in the 
study area can be described in terms of two end-member assemblages. They are 
characterized by: (1) chlorite, which is dominant in the eastern portion of the Bay; and 
(2) montmorillonite, which is dominant in the western bay region. The distribution of 
these two end-members is apparently related to source area (e.g., Gulf of Mexico for 
the Western bay area and the Atlantic coastal currents for the eastern Bay region). 
Illite is a minor component and is distributed in a manner parallel to chlorite. Kaolinite 
is also present in small quantities, but its areal distribution could not be delineated 
accurately. A restricted areal distribution of the two end-members exists due to the 
inhibiting action of many near-surface, carbonate mud banks on the exchange of water 
189 
