ATLANTIC AND CARIBBEAN PYCNOGONIDA—HEDGPETH 243 
upon the legs are much more numerous, large and more slender; the 
abdomen is much shorter and stouter. Moreover, in A. echinata 
the second joint, in at least the two posterior pairs of legs, has a very 
prominent, rounded, hair tubercle, projecting from the lower and 
posterior side, which is wanting in our species.’”’- Reexamination 
of some of Wilson’s material has revealed the presence of very low 
genital protuberances on the last two pairs of second coxae in the 
males of spinosa, but they are far from prominent. Until the larval 
development of the two species can be compared, this difference 
alone is enough to entitle them to separate names. 
Hilton (1948a, pp. 94-95) lists Ammothea echinata from San 
Francisco Bay and Alaskan waters. This cannot be Achelia spinosa, 
since ‘‘two well developed suture lines” are mentioned; A. spinosa has 
Ficure 38.—a, b, Achelia spinosa (Stimpson) Wilson; c, d, 4. scabra Wilson; ¢, A. sawayat 
Marcus; f, g, A. gracilis Verrill; h-l, A. brevichelifera, new species: h, Dorsal view of 
holotype; 7, palpus; j, leg; &, tarsus and propodus; /, terminal joints of oviger. 
