MUSEUM OF COMPARATIVE ZOOLOGY. 249 
more numerous and larger in the male. "Terminal joint elaw-like, very short 
and stout, 
Ambulatory legs (inthe female) about three times as long as the body (without 
the rostrum), slender and tapering ; 2d joint about two and one half times the 
1st or 3d, with a slight but charaeteristio elevation on the anterior side outside 
the middle ; 4th and 5th, longest, equal ; 6th, two thirds the fifth; 7th, one 
third the 6th ; 8th, less than 7th ; dactyli (Fig. 29) very short and small; those 
of the anterior pair of legs are considerably smaller than the others, but are 
unmistakably present (compare Gnamptorhynchus). 
In the male the legs are relatively shorter. The whole surface is granular 
with fine close-set tubercles. Color pale dull yellow to dusky, sometimes 
irregularly mottled with yellowish and dingy chocolate-brown, 
As shown by the measurements, the sexes differ conspicuously in size. 
Female : — Length of body (not including rostrum) . . . . 80.5 mm. 
ux เก ณี ศร ห ศศ VETERI 
di a vigi de di d cu al i ELM E 
idi เก ป กช รด ท ค ศร เห ห ร ร อ ง ห ร ด ณะ ร ซะ 
ES กบ ท o Ty sc us ca (00 O 
s A NOCT S ar Y a y m 
A moby A A nda e ow EDS 
re แก NS t , D. 
Four males and five females from locality 308, N. Lat. 41° 24 45”, W. Long. 
65° 35' 30”, 1242 fathoms. 
This is an interesting species. The accessory legs, as noted above, arise from 
distinct lateral processes, near the middle of the oculiferous segment. The 
palpi also are attached to prominent processes of the same segment. The 
presence of well-marked sexual characters in the “antenne” has not before 
been observed in the group. The male seems for some reason to retain the 
larval chelate antennæ, which undergo in the female a further retrograde de- 
velopment, and become functionally useless, 
I cannot absolutely demonstrate the specific identity of the two forms de- 
scribed. as male and female, though there can be scarcely a doubt that they are 
of the same species. They are all from the same haul, agree in every respect 
except size and the structure of the antennz and accessory legs; and the differ- 
ences of the latter correspond with those known to exist among other Pyeno- 
gonida. The sexes were determined by examination of the internal generative 
organs. 
The chelate or simple character of the “antennæ ” is commonly accepted 
as a family character, but the small value of such a distinction is shown by 
the structure of this species. A very slight further reduction of the antennæ 
in the female would bring the latter into the Achelidæ, as now defined, while 
the male falls into the Nymphonidæ. The need for an entire revision of the 
systematic arrangement of the Pycnogonida is sufficiently obvious, but no ac- 
ceptable one seems possible until our knowledge of the development is more 
complete. 
