oe 
eS 
REPORT ON THE PYCNOGONIDA. 103 
nuclei, in these cavities. This was in the first tibial joint of the leg of Colossendeis 
leptorhynchus ; however, I think there can be no doubt that these same cells will also be 
found in the other joints of the legs of this species. Each cell terminates in a long and 
slender appendage, which probably extends to within a small space of the opening of the 
canal. Most probably these are the glands which, according to Dohrn, are always present 
in these integumentary cavities. I have figured these glands in fig. 1 of Plate XVIIL: dis a 
part of the wall of the intestinal cecum, which runs through the joint ; ¢,¢ are parts of the 
septa of connective tissue, which seem to form here separate chambers in connection with 
the different cavities. These chambers contain numerous blood-corpuscles of an irregular 
spool form, and towards the pore-canal are furnished with two (2), in an other cavity 
three (d’) glandular cells, with very large nuclei. The specimen, the integument of 
which shows these glands, is a female. 
Returning to these integumentary cavities, and their ordinary, viz., their respiratory, 
function, I have still to mention that I found them in many species with many blood- 
corpuscles in their interior, and that often also a nerve is seen which sends a very thin 
branch into them. These I observed more accurately in Colossendeis proboscidea, Sab. 
(See later, under peripheral part of the nervous system.) 
The number of these cavities is different in the different species. I counted them in 
transverse sections of the fourth joint of the leg in some fourteen species, belonging to 
five genera, and compared them with the girth of the joint. This I did to ascertain if 
there was any relation between the number of these cavities and the depth at which the 
species lives. That such a relation does not exist, and that the greater or smaller number 
of these cavities is one of the properties of the natural groups (genera) of the Pycnogonids, 
is shown, I believe, by the following table :-— 
ee 
———— 
Cites | mbes, || 
- 0 etitie umber 
Name)ofither Species. is fourth Gone Ft Ap lieccand per millimeter. in Signe! 
of the leg. F 
section. 
Nymphon brevicaudatum, Miers, . 3°25 5 1°54 73 
Nymphon brachyrhynchus, Hoek, . 1°52 22 14-4 83 
Nymphon robustum, Bell, . : 46 27 59 458 
Nymphon longicoxa, Hoek, . 2°35 12 Dall 1100 
Nymphon hamatum, Hoek, . : 3°47 37 10°7 1488 
Ascorhynchus orthorhynchus, Hoek, 34 90 26°5 130 
Ascorhynchus glaber, Hoek, . ‘ 3 56 18°6 1375 
Colossendeis proboscidea, Sab. (sp.), 10:2 106 10 540 
Colossendeis leptorhynchus, Hoek, 3°37 63 18-7 1126 
Colossendeis brevipes, Hoek, . 3°15 62 20 2650 
Pallene australiensis, Hoek, . 2°4 20 83 79 
Phoxichilidium insigne, Hoek, 1:57 41 26 14 
Phoxichilidium patagonicum, Hoek, 5:2 112 21°5 117 
Phoxichilidium pilosum, Hoek, 417 45 10°8 1790 
