74 THE VOYAGE OF H.M.S. CHALLENGER. 
The ovigerous legs are of the ordinary form. Only the middle of that part of the 
surface of the four last joints which is turned inwards, is furnished with denticulate spines. 
Their form is very peculiar, being flattened and much broader towards the extremity 
(Pl. X. fig. 14). They are not very numerous and are placed in three rows only, 
while every row contains about six of them. The margin of the spines is smooth. 
The claw of the ovigerous leg is small, and the length of the several joints is as in the 
other species of the same genus. 
The legs are extremely long and slender. ~ With the exception of some small but 
strong hairs, like those of the palpus, they are smooth. The first three joints are small ; 
of the three following the first two (the fourth and fifth) are nearly of the same length, 
whereas the sixth is considerably shorter, but much longer than the last two joints 
together. Of these the first (the first tarsal joint) is about once and a half as long as the 
second. The claws at the ends of the legs are about half as long as the second tarsal joint. 
About the sex of the only specimen collected I am unable to form an opinion. 
Perhaps it is not yet quite adult: extremely small genital pores are to be observed 
ventrally on the second joint of every leg. 
Habitat.—This interesting little Colossendeis was dredged by the Challenger at 
Station 50. May 21, 1873. Lat. 42° 8’ N., long. 63° 39’ W. Depth of the sea, 
1250 fathoms. Temperature of the bottom, 2°8° C. Bottom of the sea, grey ooze. 
Observations.—This curious form is intermediate, I believe, between the short-nailed 
Colossendeis leptorhynchus, with its extremely long proboscis, and the long-nailed Colos- 
sendeis gracilis, with the comparatively short proboscis. The difference in length between 
the third and the fifth joint,—in Colossendeis leptorhynchus the fifth joint is the longest, 
and in Colossendeis gracilis it is the third joint which has the advantage—has almost dis- 
appeared in Colossendeis minuta. 
The species was dredged about two degrees south of Halifax ; though the Pycnogonids 
of the neighbourhood of the coast of New England are comparatively well known, the 
occurrence of a species of Colossendeis in those regions has not been recorded as yet. 
And this, no doubt, is due to the circumstance that the species in question inhabits deep 
water, while hitherto only the shallow water inhabitants have been carefully investi- 
gated. 
Discoarachne, n. gen. 
Diagnosis.—Proboscis stout, cylindrical, tapering towards the extremity. Mandibles 
wanting. Palpi five-jointed. Ovigerous legs not furnished with denticulate spines, ten- 
jointed. 
Discoarachne brevipes, n. sp. (Pl. VII. figs. 8-12). 
Diagnosis.—Body disciform, consisting of the true body without any segmentation 
