ATLANTIC AND CARIBBEAN PYCNOGONIDA—HEDGPETH 24] 
7. Chelifores 3-jointed; trunk segmentation distinct_.__.___..._._._--__---_------ 8 
Chelifores 2-jointed; trunk segmentation usually suppressed_Achelia (p. 241) 
8. Propodus intermediate; proboscis short, cylindrical____Ephyrogymna (p. 261) 
Propodus well developed; proboscis large, elliptical or pyriform, 
Ammothella (p. 246) 
Genus ACHELIA Hodge, 1864 
Chelifores 2-jointed, usually subchelate in the adult. Palpi 7- 
to 9-jointed, usually 8. Oviger 10-jointed, with leaflike denticu- 
late spines but without a large terminal claw. Propodus well de- 
veloped, with prominent auxiliary claws, but heel and basal spines 
lacking in some species. The trunk is usually compact and circular, 
but there are at least two species from deep water with elongate, 
segmented trunks. 
In this genus are included the small forms without a completely 
segmented trunk which have been referred to Ammothea Leach, 1814 
(=Leionymphon Mobius, 1902) by many authors, or to the subgenus 
Achelia of Ammothea by others (Giltay, 1934b). The principal 
distinction of Ammothea, aside from its larger size, is the presence of 
prominent annular swellings or ridges between the trunk segments. 
One reason for this confusion has been the apparent mistake in the 
type locality of Ammothea carolinensis Leach (1814, pp. 33-34). 
Leach believed that the specimens came from South Carolina and 
named them accordingly. Calman (1915b), in redescribing the holo- 
type, suggested that this may have been an error for South Georgia. 
Except for dubious records, the genus Ammothea s. str. is known only 
from the Antarctic and sub-Antarctic regions.” The only species of 
pycnogonids so far known from the coast of South Carolina are 
Anoplodactylus lentus, Endeis spinosa, Nymphopsis duodorsospinosa, 
and Tanystylum orbiculare. Ammothea carolinensis has been frequently 
collected from South Georgia, and there is little doubt that Calman’s 
suggestion is correct. 
Helfer, in the Bronn’s Tierreich Monograph (Helfer and Schlottke, 
1935, p. 284) has confused the matter by first reducing Achelia to 
synonymy under Ammothea, then including the genotype of Ammothea 
under the name Leionymphon while at the same time recognizing 
Ammothea Leach. As Marcus (1940b, p. 69) has rather pointedly 
remarked, ‘Helfer did not comprehend the nomenclature of the 
Ammotheidae.” 
There are a number of dubious names, viz, Alcinous Costa, 1861,_ 
Phanodemus Costa, 1836, Platychelus Costa, 1861, Oiceobathys Hesse, 
1867, and Oomerus Hesse, 1874, which may be congeneric with Achelia, 
but it seems wisest to forget them. The punctilious taxonomist 
who endeavors to resurrect such names will not be thanked for his 
pains. 
23 Loman (1929, p. 71) reports an immature Ammothea (Leionymphon) from the Atlantic coast of Morocco 
and Hilton (1948a, pp. 97-98) proposes a new species, Leionymphon dorsiplicatum, from the North Pacifie. 
