488 



Fishery Bulletin 105(4) 



B 



70 

 - 60 



H 40 

 § 30 



o 



I 20 ^ 

 i 

 w 10 



2 4 6 8 10 12 14 16 

 Elapsed time (min) 



Figure 1 



(A) Experimental setup showing a whelk, the osphradium chamber (modified syringe barrel), the aerated, filtered, and 

 ultraviolet sterilized water (FSW) and odorant solution delivery tube, and the micromanipulator holding the suction elec- 

 trode. (B) The predicted growth (solid line) and decay (dashed line) of the concentration of stimulus within the osphradium 

 chamber over the course of a 15-minute trial, expressed as a percentage of the original odorant solution concentration. 



1 2 

 1.0 - 



> 



E 



B 



V^V\Vt1^*^VlfiAMil^^4AM 



/-^. 



E 



300 msec 



Elapsed time (minutes) 



Figure 2 



(A) Activity in the pallia! nerve in a channeled whelk tBusycotypus canalicutatum) before and during exposure of the 

 osphradium to an odorant solution prepared from horseshoe crab [Limulus polyphemus) eggs. The arrow in panel B indi- 

 cates the approximate initial entry of the odorant solution into the osphradium chamber. The two brief large increases 

 in activity (occurring at approximately 2 and 11 minutes after the start of the record) were associated with slight move- 

 ments of the animal. (B) Nerve activity integrated over 10.2-seeond intervals was documented with Dasylab 7.0 software 

 (National Instruments Corp., Austin, TX). (C) Nerve activity recorded before initial entry of the odorant solution into the 

 osphradium chamber (3 minutes after the beginning of the record shown in Panel A). (D) Nerve activity at the apex of 

 the response to the odorant solution (8 minutes after the beginning of the record shown in Panel A). 



recorded 5 minutes immediately before and 5 minutes 

 immediately after the initial introduction of an odorant 

 solution were analyzed. This procedure resulted in ap- 

 proximately thirty equally spaced data points (i.e., one 

 data point recorded every 10.2 seconds for five minutes). 



representing integrated nerve activity in each time 

 period (Fig. 2B). The area under the curves represent- 

 ing integrated nerve activity (Fig. 2) was calculated by 

 summing the points from each 5- minute period (i.e., 

 the data recorded before and during presentation of an 



