248 
NATURE 
[Fuly 24, 1873 
The parts of the mouth are normal, The three first 
pairs of ambulatory legs are terminated by chelz, the 
fourth pair bear recurved claws, and the fifth abortive 
stump-like claws. The chele of the first pair of 
legs are strangely developed, particularly the right 
chele, which is double the length of the left, 
and with its formidable ranges of long spines along 
the inner border of each claw reproduces on a small 
scale the jaws of the Gangetic gavial. The last 
segment of the pereion is not covered by the carapace 
but is in moveable connection with it. The first segment 
of the abdomen is very sinall, and the segments gradually 
increase up to the fourth, which the fifth and sixth equal 
in size. The abdominal segments are flattened from 
above downwards. The telson is quadrate, and com- 
bines with the two pairs of caudal appendages, which 
are widely expanded laterally to form the caudal 
fin. The dorsal surfaces of the second, third, and fourth 
abdominal segments, and the margin of the tail, are 
thickly covered with woolly hair. The individual being a 
male, the first pair of swimmerets consist of long slender ap- 
pendages, and the four succeeding pairs have one strong, 
round, basal joint, to which are attached two palpi fringed 
with hair. There is some resemblance between this 
form and Caé/ianassa, but in this genus the lamellar 
appendage to the outer antenna is absent. There are 
four pairs of limbs with chelz instead of three, and the 
carapace is soft. 
To the genus 4stacus, therefore, with which it has all cha- 
racters in common except the great development of the 
right chela and the total absence of eyes—neither charac- 
ters of generic value—the present species must be referred. 
A, Zaleucus,n. sp. (Fig. 1). 
Rostrum spiny, elongated. Lamellar appendage of 
the outer antennz reaching to the middle of the second 
joint of the funiculus. Chelz on three pairs of ambulatory 
feet, those on the first pair strongly but unequally deve- 
loped. Cephalothorax very much compressed laterally, 
eyestalks and eyes entirely wanting. 
On Sunday, March 16, we anchored in the Gregaria 
Channel, at the entrance of the harbour of Charlotte 
Amalia. We spent a few very pleasant days at St. 
Thomas, some of the civilians of our party enjoying 
greatly their first experience of life and scenery within 
the tropics. M. Gardé,the Danish Governor, received 
us with the most friendly hospitality. He is a naval 
man, and was greatly interested in our investigations, and 
his Aide-de-Camp, Baron Eggers, had collected and worked 
out the plants of the Island with care, and was other- 
wise well acquainted with its natural history. 
The natural history of the island of St. Thomas is 
tolerably well known, and large collections of its fauna 
and flora have been sent home from time to time by very 
competent naturalists to the Museum at Copenhagen. 
On the present occasion our time was much too limited 
to attempt to make collections, so the naturalists 
contented themselves with a little shallow water dredging, 
and such a general survey of the island and shores as 
might familiarise them with the more characteristic forms 
of animal and vegetable life ; for while the Atlantic Islands 
Madeira, and the Canaries, although gradually assuming 
a more tropical character, maintain the most intimate 
relations in natural products with the south of Europe, in 
Tropical America everything is changed, and it takes a 
little time to become familiar with new acquaintances 
whom one has hitherto known, if he has known them at 
all, only from descriptions or figures, or at best mummied 
or pickled, or otherwise in inadequate effigy. Ophiurideas 
are particularly plentiful at St. Thomas, and. we made 
large collections of these, particularly of the many large 
and characteristic West Indian species of the genus 
Ophioderma. 
On the 24th of March we left the harbour of Charlotte 
Amalia and proceeded with a light north-easterly breeze 
towards the Culebra passage. The next morning we 
sounded in 625 fathoms. The ooze was closer and more 
free from shells and coral than in the former haul, but 
otherwise much of the same character. This time the 
dredge came up about half full, and on sifting its con- 
tents many interesting additions were made to our collec- 
tions. Here we met for the firststime with the curious 
little crinoid, Rhzzocrinus lofotensis, for which we had 
been on the outlook since the beginning of the cruise, 
and Salenia varispina, which we now recognise as a 
very widely distributed inhabitant of the deeper water. 
This elegant little urchin (Fig. 2) is about 1omm, in 
diameter of the test. It resembles in general appearance 
young specimens of Czdaris hystrix. The ambulacral 
zones are narrow, the interambulacral correspondingly 
wide, and both are furnished with double rows of flat, 
paddle-shaped, secondary spines beautifully striated in 
purple and white, ranged along the middle line, from 
which they shed outwards on either side. The primary 
tubercles are large, imperforate, and distinctly crenated. 
Some of the larger of the primary spines are 50mm. in 
length, “8mm. in diameter, and cylindrical, gradually 
tapering towards the point. They are fluted and serrated 
along the ridges with sharp prickles. The spines in all 
the specimens we have dredged are very uniform ; some 
are slightly curved, but they scarcely agree with the de- 
scription given by Prof. A. Agassiz, from a young speci- 
men, of being “of all shapes.” The spines round the 
mouth are short, some of them slightly, flattened and 
sharply denticulated. 
The corals which were abundant in individuals were 
all deep-water forms, They have been examined by Mr, 
Moseley, who refers the majority to species which have 
been described by M. de Pourtalés* from the Straits of 
Florida. 
Two examples of the sponge-body of a very handsome 
Hyalonema were sifted out of the coral.mud. Unfortu- 
nately in both cases the sponge had been torn from the 
central coil, and the absence of the coil might have thrown 
some little doubt upon the form and mode of finish of the 
complete animal, so that it was extremely fortunate that a 
young specimen of the same species about 40 mm. in 
length was caught in the tangles quite perfect. 
Hyalonema toxeres, new species, resembles closely the 
other known species AH. Jusitanicum and H. sieboldi in 
general appearance and in the arrangement of its parts. 
A more or less funnel-shaped sponge presents two sur- 
faces covered with a network of different patterns formed 
by varying arrangements of large fine rayed spicules. 
The upper concave surface shows a number of oscular 
openings irregularly arranged, and the lower surface a 
more uniform network of pores, some of which seem to 
be irhalent and others exhalent. 
The central axis of the sponge is closely warped into 
the upper part of a coil of long and strong glassy spicules 
which, as in the other species, serve to anchor the sponge 
in the soft mud. Both of the species dredged have the 
sponge more flattened and expanded than it is in HZ, /usz- 
tenicum. In one of them it is nearly flat (Fig. 3), forming 
a reniform cake-like expansion 80 mm. in length by 7omm. 
in width, and about 8mm. in thickness. The upper or 
oscular surface is covered by an exceedingly close net- 
work with groups of large openings at nearly equal inter- 
vals. It is slightly raised in the centre. The central 
elevation is followed by a slight depression, and the upper 
wall then passes out nearly horizontally to a sharp peri- 
pheral edge fringed with long delicate spicules, each 
consisting of a slender central shaft with a cross of four 
short transverse processes in the centre. The outer half 
of the central axis is delicately feathered. The lower 
surface of the sponge (Fig. 4) is protected by a singularly 
* Tilustrated Catalogue of the Museum of Comparative Zoology at 
Harvard College, No. 4—Deep-sea Corals. By L. F. de Pourtalés, Cam- 
bridge (Mass.), 1871. 
