COLOSSENDEIDAE n 



the latter are available, it becomes evident that certain of these differences are no 

 longer valid. 



In D. antorctica the number of segments in the palp is variable (8-10, see Table I, 

 Fig. i; Caiman, 1920, p. 245, figs. A and B). This extreme variabihty is most 

 unusual in Pycnogonida, where the palp has, as a rule, a constant number of segments 

 in each species. Since it is not yet certain that this is a quite normal phenomenon, it 

 has been dealt with under "Abnormalities" (p. 130). 



According to Bouvier (1906, p. 28) the legs are considerably longer in D. antarctica, 

 being approximately twelve times the maximum width of the trunk instead of only 

 8-9 times as in D. australis. In the Discovery specimens the two species are ahke in 

 this respect, for while the ratio varies from 9-3 to i2-8, the average is 10-84 for 

 D. australis, 10-90 for D. antarctica. 



In D. antarctica the two sexes do not differ from each other with regard to the relative 

 width of the trunk (Table I). The chief differences between the two species are 

 given in Table I ; the outstanding characteristics of D. antarctica are (i) the broad ocular 

 tubercle, (2) the slightly arched fingers, and (3) the long, slender first joint of the 

 chelophore. 



Encrusting organisms, mostly Polyzoa and sponges, are found with far greater 

 frequency on specimens of D. antarctica, suggesting that it is probably of more sluggish 

 habits than D. australis (see p. 132). In the male from St. 123 the left chela is rendered 

 quite useless by a growth of Polyzoa, and in the specimen from St. 140 the ocular 

 tubercle is partially concealed. 



Distribution. See p. 4. 



Family COLOSSENDEIDAE, Hoek 



Genus Colossendeis, Jarzynsky 



Two species are described as new, although, when more material is available, one of 

 these may prove to be a sub-Antarctic form of a common Antarctic species. The other 

 species is remarkable for the lateral articulation between the seventh and eighth palpal 



segments. 



The key to the " Longitarsal " species of Colossendeis drawn up by Caiman (1915, 

 pp. lo-ii) is reprinted below with slight modifications, chiefly those required by the 

 incorporation of the two ntW'f species. 



I. Sixth segment of palp more than three times as long as wide. 

 A Proboscis distinctly longer than trunk. 



I. Trunk segmented C.articulata, hom'^n 



II. Trunk non-segmented. 



A. Lateral processes in contact. 



1 . Seventh segment of palp longer than eighth; eyes absent. ..C. proboscidea (Sabine) 



2. Seventh segment of palp shorter than eighth; eyes present C. scotti. Caiman 



