ATLANTIC AND CARIBBEAN PYCNOGONIDA—HEDGPETH 163 
The most interesting feature of the fauna of the western Tropical 
and Subtropical Atlantic is the occurrence of several small species, 
previously known from the eastern shores of that ocean. In the 
following discussion this distribution is attributed to the dispersing 
influence of ocean currents rather than to evolutionary convergence. 
Certainly the large number of closely related species in the Pycno- 
gonida suggests a tendency toward divergence. On the other hand, 
the occurrence of decapodous species in widely separated families 
might be considered an example of convergence, although it is equally 
possible that it is simply the result of a basic similarity of chromosome 
pattern among the groups concerned. It may be significant that the 
distribution of these 10-legged pycnogonids appears to be localized 
or continuous insofar as it is known, i. e., there seem to be no im- 
portant gaps in the ranges of the various species. Furthermore, as 
far as we know, they are restricted to the Antarctic and the Caribbean. 
I have discussed the problem of 10-legged pycnogonids in greater 
detail elsewhere (1947). 
This zoogeographical discussion is confined to the shallow-water 
and littoral species, the distribution of which is more subject to 
geographical features and surface currents than that of the deep- 
water species. The species of pycnogonids known to occur in the 
western North Atlantic are listed in table 1. 
TABLE 1.—Distribution of Pycnogonida found in the western North Atlantic and the 
Caribbean 
{Species in brackets found occasionally in American waters south of lat. 60°. 
S=surface tow or sargassum records. P=deep pelagic tows] 
De |ltsiee Sl | es ay |G. QD ale D in 
3/2 fe | 8 Bilge) |ge| (esl | 28 
<2 ae Ag & a Ss 2 (S) sea 8 
S| Ol\_s ° a (S25 ia) @ |yolen = 
22/2 5/ES| ~g2 a |e | 8 |28/38| e¢ 
Species SSlIS8/82] 98 ola SE lemeehsoi@e as 
Hsised\/oQl Sa > 3G iS) ao |o c am 
43/5 :|A5|/ 07> | 3] 2/8 mz | 8 |,8] 2] 98 
4 aS|ee Bt Bole cea li ceieelons Bs 
gg\*~l, lim iy = lea aie aS a= 3 |£sis aa 
@ (4 ja2 |S jaja jale?| = See | as 
NYMPHONIDAE: : 
Nymphon spinosissimum Fathoms 
(Norman) Re 8 | Xe (a alee a Eas Bg | we ell) RN || a ie 190-471 
hirtipessBell == >. Gy [eeeee| eG eee Peel het a hata eh sete) a lb «eel eS eed 25-218 
tenellum (Sars) -------- S| | FE 2a | ae Cea ree (ce | et aoe | Re ee Wen RN | |S 218-938 
grossipes (O. Fabr.?) 
Rr Oyereat= te oan Pap] | 221d, Gh | bP Gg |e a Son eel Wee IO a sha | unt lit.-677 
[brevitarse Krdyer-____-- DG ee (eee Bs Spe ea [ad Pa Eee Pata |e tana ee na Sublittoral] 
longitarse Krdyer_____- 2G | ES E>: | iene). be ee ae | ferme | Nabe UM Sf] a8 oats | ute. 16-155 
(428f) 
stro6mi Krgyer___..__-- SIRS | Soc | ORSig He RE | OH MC I a ee BRIS || ko RS ER 7-524 
(elegans Hansen______- >. (=a eee | SRS Fe Mh inal Nhe 58 aa a eal ely Ee | 314] 
rubrum Hodge_____-_-- 1 |S oe > Ge Soles) a eee (a be REA feed 2 Se aa Sublittoral 
macrum Wilson. -_---- Di (i: |. Gl >. aa eae ae | ee, Clee We, Ca oe le pla re 35-843 
[sluiteri Hoek ______-_- Oy. | Ee tT (7) J fetes prey | ese | ee em | ae | FI ee weet Abt. 100] 
CULAYTRME WiSDOCIES ee |e xis | etme | |e a ES a ls ee (?) 
floridanum, new spe- | 
CATS ASR RS SS oe EU re fi ea es ee ee | >: 1 (ps rae aE Pann ie | S-30 
