PYCNOGONIDS 265 
especially broad in the female, where it may equal the width of the pro- 
boscis; at the dorsodistal border is a long conical protuberance armed 
with a strong spine which usually projects distally; “41 and #2 equal, 
stout; all these joints armed more or less densely with moderate spines, 
which are longer, however, on the dorsal side of 41 and “4.2. First tarsal 
joint small, subtriangular, with short, even spines; ¢s.2 moderately 
strong, arcuate, armed dorsally and on the sides with rows of slender 
spines, and ventrally with 3 strong spines at the heel and a row of 
very short ones along the sole; c/. about one half #s.2.; aux. cl. well 
developed, half as long as c7, In the male the genital projection on the 
ventrodistal side of ¢.2 of the 2 posterior pairs of legs is pronounced 
and thumb-like, and provided with 1 or 2 slender bristles. As is charac- 
teristic of the genus, the genital openings of the female are in a corre- 
sponding position on all 4 pairs of legs, but are not situated on similar 
protuberances. 
Length about 4 mm., extent 16 mm.; the two sexes nearly the same 
size. 
Immature specimens.—Four immature specimens of this species were 
examined, two from each locality where the form was taken. They are 
but little smaller than the adults, which they closely resemble, but are 
provided with chelate chelifori (pl. xvm, fig. 1), and the ovigera are very 
short, with indistinct articulations (fig. 2). It is interesting to note that 
the denticulate spines are already forming in this early stage, in a space 
beneath the outer cuticle (fig. 3), and at the next moult would probably 
be free. If any of these specimens were males there was no trace at this 
stage of the genital protuberances; in fact, the genital openings were not 
distinguishable at all. 
SPECIMENS EXAMINED. 
Lot. Locality. No. of specimens. Date. Source. 


———. 1 |St. Paul Island, | 2, 39, 2juv.| 1897 | Prof. Kincaid (123) 
Pribilofs 
4 Dutch Harbor, | 17, 39, 2 juv.|July, 1899] H. A. E. (Prof. W. R. Coe) 
Unalaska 

Remarks.—Whereas Ammothea alaskensis may be taken as the repre- 
sentative of 4. /evis (Hodge) in the Western Hemisphere, 4. Zatifrons 
more closely approaches those forms grouped about the European species 
A. echinata (Hodge). It may readily be distinguished from any described 
species, however, by its very broadly elliptical proboscis and the long, 
knobby chelifori and caudal segment. This species is about twice the 
size of A. echinata. 
