FISHERY BULLETIN: VOL 71, NO. 4 



KEY TO THE SPECIES OF 

 EUCALANUS 



(Adult Females Only) 



Based on integumental organs, all sites are 

 tergal unless specified otherwise. 



1. Mxp with four or more pairs 

 of sites; ThIII and IV lacking 

 single middorsal site between 

 anterolateral hair sensilla; 

 ThIV lacking paired sites 

 lying outside of dorsal quad- 

 rangle of hair sensilla 2 



Mxp usually with two pairs 

 of sites; ThIII and IV with 

 single middorsal site lying be- 

 tween anterior two hair sen- 

 silla; ThIV with one pair of 

 sites lateral to quadrangle 

 formed by four hair sensilla 3 



2. Mxl and Mx2 with total of 10 

 sites forming a rectangle and 

 arranged anterior to posterior 

 in two bilateral sets of one 

 pair, one single and one pair of 

 sites; Thll and III in lateral 

 view with three sites, Abd.IV- 

 V with at least three tergal 



sites attenuatus group, 4 



Mxl and Mx2 sites vary from 

 8 to 18 in number, not arrang- 

 ed in rectangle pattern, poste- 

 rior sets more lateral than 

 anterior sets; Thll and III 

 with one or two lateral sites; 

 Abd.I-II with at least two ter- 

 gal perforations elongatus group, 5 



3. ThIII and IV with one medial 

 site in tergal arc formed by the 



tergal sites subtenuis group, 6 



ThIII and IV with two medial 

 sites in the arc formed by the 

 tergal sites pileatus group, 7 



4. A. Abd.III with tergal site B 



Abd.III lacking tergal site C 



B. Abd.I-II usually with one 

 site, Abd.IV-V with three 



tergal and one pleural site parki 



Abd.I-II usually with two 

 sites, Abd.IV-V with at 

 least four tergal and three 

 pleural sites langae 



C. Abd.I-II lacking tergal 

 sites, Abd.IV-V usually 

 with five tergal and zero 



pleural sites seivelli 



Abd.I-II with two tergal 

 sites, Abd.IV-V with three 

 tergal, usually two or more 

 pleural sites attenuatus 



5. A. Thll and III with a pair of 

 sites anterolateral to arc 

 formed by tergal sites; 

 Mxl and Mx2 with at 

 least 16 sites B 



Thll and III lacking a pair 

 of sites anterolateral to 

 arc formed by tergal sites, 

 Mxl and Mx2 with 12 or 

 fewer sites D 



B. ThI and II each with seven 

 tergal sites; Abd.I-II with 



three tergal sites hyalinus 



ThI with 13, Thll with 

 nine tergal sites; Abd.I-II 

 with four tergal sites C 



C. Mandibular basis with one 



seta californicus 



Mandibular basis with three 



setae bun git 



D. Al somite with sets of 

 eight and four sites; Mnd 

 somite with six sites; ThV 

 with three sites; Abd.I-II 

 with two sites, Abd.III and 

 IV lacking tergal sites, 



Abd.IV lacking pleural sites . . inermis 



Al somite with sets of six 

 and two sites; Mnd somite 

 with two to four sites; ThV 



f 



998 



