FISHERY BULLETIN: VOL. 72, NO. 1 



0.2 mm 

 I 1 



c,d 

 0.2mm 



a,b 



Figure 7. — PontelUna platychela sp.n., adult male: a. P5, posterior view (Atlantis //-20-24); b. P5 chela, lateral view 

 (same as a): c. ThIV-V and P5, lateral view (Atlantis 11-20-27); d. range of variation in ThIV-V (left to right: 3 specimens 

 Amazon 17; La Creuse 7; Oregon 1293). 



3.52:1; right furcal ramus length 0.110 mm, 

 width 0.075 mm; from same sample as male. 

 USNM No. 141614. 



Paratypes: 3c5 , 89 from same sample. USNM 

 No. 141615. 



Reference specimeji.s: 56, 5 (^ , Oregon stn. 

 1293. lat. 19°55'N, long. 74° lO'W, 23 Apr. 1955, 

 G III net towed between surface and 2m. 

 USNM No. 141616. 



Distribution 



P. platychela was found only in epipelagic 

 tows taken in equatorial latitudes of the Atlantic 

 Ocean (Figure 8). The species appeared regular- 

 ly in samples collected between lat. 10° S and 

 10° N. The more extensive sampling available to 

 us from north of the equator indicates that few 

 platychela extend as far as lat. 21° or 22°N and 

 that the species disappears abruptly at high- 

 er latitudes. We anticipate that in the vicinity 

 of the Gulf Stream its northward occurrence 

 may be extended somewhat by examination of 

 additional samples, paralleling occurrences 

 to the south in the Brazil Current. 



Additional Description 



Female 



Right furcal ramus somewhat shorter than in 

 plumata (see Figure 27), typically 1.4 times 



78 



longer than wide (median 1.44:1, range 1.28- 

 1.55:1, 35 specimens), lateral process anterior 

 to proximal seta lacking, but interior of ramus 

 with glandlike tissue and ductiike structure 

 leading to lateral margin as in plumata. 



P5 (Figure 6e) essentially as in plumata 

 including proportional length relationship of 

 Re and Ri, median 2.27:1, range 1.69-2.91:1, 

 49 specimens (see Figure 29); Ri polymorphic 

 with one or two apical spines fused to segment, 

 in same specimen spines on left and right Ri 

 may differ in number as in plumata (Figure 6i, 

 Table 7). 



Attached spermatophore observed in one 

 specimen (see Figure 33c-e, Table 5); neck 

 cemented to ventral side of genital segment in 

 vicinity of genital pore and buried within large 

 irregular mound of cement extending across 

 entire length of genital segment and right 

 ventral side of anal segment, neck extending 

 to right anterolateral side of anal segment along 

 with continuation of cement fixing it to anal 

 segment, large helical counterclockwise turn 

 following emergence of neck from cement 

 orienting succeeding sac anterodorsad. 



Male 



Right furcal ramus as in plu mata (see Figures 

 19, 26), but relatively wider (see Figure 28), 

 ratio of length to width typically 2:1 (median 

 2.06: 1, range 1.91-2.34: 1, 37 specimens). 



Our impression from the available Atlantic 



