100 PERCY SLADEN TRUST EXPEDITION. 
Indeed, among the specimens of the present collection, the single male from the Saya 
de Malha Banks differs from the Maldive types, being larger (10 mm. long) and having 
the claw of the foot relatively longer (half as long as the propodus). 
The delicacy and transparency of these Rhopalorhynchi have rendered possible a 
superficial examination of the nervous system; the chain of ventral ganglia are — 
arranged as shown in fig. 27. As usual, the ganglia of the first leg-bearing segment are 
closely associated with the subcesophageal ganglionic mass, while the great anterior 
extension of both the second and third leg-bearing segments leads necessarily to a wide 
separation between the ganglia of these segments from one another and of the second 
from the first, while the ganglia of the fourth leg-bearing segment lie immediately 
behind those of the third. ‘This differs from the ventral nerve-chain of Colossendeis, as 
figured and described by Hoek (1881, pp. 112-113, pl. 17. fig. 2), in which the ganglia 
of the fourth leg-bearing segment are connected with those of the third by connective 
nearly as long as those between the third and the second. The striking external 
distinctions between Colossendeis and Rhopalorhynchus thus find some parallel in the 
internal structure, and additional support is afforded to the separation of the two genera 
as advocated by the present writer (1893, p. 22) and lately supported by Schimkenitsch 
(1906, p. 18). The remarkably abbreviated abdomen of Rhopalorhynchus, which is 
wedged between the two hindmost lateral processes, and has the anus looking directly 
ventralwards, is also shown in fig. 27 of the present paper. 
REFERENCES. 
1893. Carpenter, G. H—Reports on the Zoological Collections made in Torres Straits by Professor A.C, ~ 
Haddon, 1888-9.—Pycnogonida. Sci. Proce. R. Dublin Soe. viii. 1893, pp. 21-7, pl. 2. 
1904, Report on the Pantopoda collected by Professor Herdman at Ceylon in 1902. Ceylon 
Pearl Oyster Fisheries, 1904.—Supplementary Report, xiii. 
1905. Notes on the Segmentation and Phylogeny of the Arthropoda, &c. Quart. Journ, Mier. 
Sci. xlix. (1905) pp. 461-491, pl. 28. 
1904. Cole, L. J—Pyenogonida of the West Coast of North America. Harriman Alaska Expedition, x. 
pp. 249-298, pls. 9-26 (1904). 
1881. Dohrn, A.—Die Pantopoden des Golfes von Neapel, u.s.w. Fauna und Flora des Golfes von 
Neapel, ili. Leipzig, 1881. 
1906. Gardiner, J. Stanley.—The Indian Ocean. Geogr, Journ. 1906, pp. 313-332, 454-471 and map. 
1885. Haswell, W. A.—-On the Pycnogonida of the Australian Coast. Proc. Linn. Soc. N.S. Wales, ix. 
1885, pp. 1021-1084, pls. 54-37. 
1881. Hoek, P. P. C.—Report on the Pyenogonida dredged by H.M.S. ‘Challenger.’ ‘ Challenger ’ 
Reports, Zoology, 1. pt. 10 (1881). 
1904. Lankester, E. R.—The Structure and Classification of the Arthropoda. Quart. Journ. Mier, Sei, 
xlvii. (1904). 
1899. Meinert, F..—Pycnogonida. Danish ‘ Ingolf’ Expedition, ili. pt. i. (1899). 
1891. Sars, G. 0.—Pyenogonida. Norwegian N. Atlantic Expedition, Zoology, vi. (1891). 
1906. Schimkenitsch, W.—Ueber die Periodizitiit in dem System der Pantopoda. Zoolog. Anz. xxx. 
1906, p. 1-22. 
1880, Wilson, E. B.—The Pyenogonida of New Engiand and adjacent Waters. Report U.S. Fish 
Commission, 1878, pt. 6, pp. 461-506, pls. 1-7. 
1873. Wood-Mason, J.—On Rhopalorhynchus kréyeri, Journ. Asiat. Soc. Bengal, xlii. (1878) pp. 172- 
175, pl. 13. See also Ann, Mag. Nat. Hist. ser. 4, xii. (1873) pp. 342-345. 
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