FISHERY BULLETIN: VOL. 71, NO. 4 



Table 3. — Total number of lateral and dorsal perforation sites, by body and abdominal segments in 



specimens examined. Body segments indicated by corresponding appendages. 



•80% of Eucalaniis 



'Lateral perforation not counted. 



VARIATION AT DESIGNATED SITES 



As described above designated sites are those 

 topographic positions on each segment occupied 

 by an integumental organ of a morphologically 

 specified type that occur within the context of a 

 relatively fixed pattern on each segment. The 

 pattern on each segment is primarily character- 

 istic of the species and includes elements charac- 

 teristic of the species group and of the genus as 

 well. 



No variation was observed in the morphologi- 

 cal nature of the organ occupying the designated 

 site during occasional examination of randomly 

 selected intact specimens or in the characteristic 

 type of perforation observed at the site in the 

 sample of the species that was examined. Small 

 differences in the relative distance between adja- 



cent sites within the pattern of a segment were 

 observed frequently. They are negligible, how- 

 ever, with respect to influencing the accuracy of 

 recording details for each specimen. Replicate 

 counts of the same specimens taken on subse- 

 quent days usually yielded similar results; the 

 few departures from zero variation ranged 

 from 1 to 3% . Spatial variation was not examined 

 closely. Better understanding of its significance 

 should be developed, as it probably reflects 

 individual morphogenetic and possibly genetic 

 differences. 



Quantitative variation in terms of failure to 

 find a perforation at a designated site or finding 

 a perforation in excess of the regular number j 

 characterizing the segment (Table 3) is remark- 

 ably low. To the extent that spatial variability! 

 does occur, it may be argued that the basic 



978 



