Figure 2.-Delphinus delphis: Specimen no. WFP 221. 



Figure 3. -Typical appearance of dermal-epidermal boundary of 

 skin of Delphinus delphis (WFP 221 sample no. 10 in Table 1). 

 Note concentration of pigment granules around bases of dermal 

 papillae and in bands extending from ends of papillae. Mag- 

 nification 1,250 diameters. 



greater prominence of diffuse pigment. In gray 

 samples from the flank patch, large grains were 

 present, but the small grains were most 

 prominent. Samples of black skin from flippers 

 and flukes showed the highest densities of large 



grains, which were more prominent than the small 

 grains. 



The histological evidence (summarized in Table 

 2) supports the concept of interacting color pat- 

 tern components. As indicated previously, the 

 spinal field may be described as a result of the 

 interaction of the pigmentation of the cape and 

 the dorsal field. The buff colored thoracic patch 

 (i.e., the cape) contains relatively high concentra- 

 tions of diffuse pigment, while in the grey flank 

 patch (i.e., the dorsal overlay) granular pigment is 

 more prominent. The spinal field is characterized 

 by a larger amount of diffuse pigment than is 

 present in the flank patch, and a larger amount of 

 granular pigment than is present in the thoracic 

 patch. The high concentration of grains in the 

 spinal field indicates a possible synergistic effect 

 of the two component systems. 



Perrin (1972) suggested that the flukes are pig- 

 mented only as part of the cape system. The skin 

 of the flukes (sample no. 13) contained large 

 amounts of all three types of pigment, indicating 

 that pigmentation of the flukes involves both the 

 cape system and the dorsal overlay system. The 

 skin of the flipper (sample no. 8) also contained 

 large amounts of all three types of pigment. 



The major difference between samples taken 

 from WFP 125 (female) and those taken from 

 WFP 221 (male) was that the epidermis was 

 thicker (0.75-1.70 mm as opposed to 0.50-0.95 mm) 

 in the latter animal. Thus a lower density of pig- 

 ment was required to produce the same color. Also, 

 the samples taken from the buff -colored area of 

 WFP 221 showed conspicuously less diffuse pig- 

 ment. 



441 



