278 DISCOVERY REPORTS 



Other characters specified in the present and in previous descriptions of the species. It 

 is remarkable that microscolecine reduction of the prostates sliould have occurred with- 

 out involving any other characters, even the posterior pair of spermathecae being 

 normally developed. 



Length 37-40 mm. Colour slightly pigmented greyish brown dorsally and ventrally 

 at the anterior end. Prostomium schizo-epilobic. Clitellum 13-16 ; in the fully clitellate 

 specimen the clitellum is complete but much less swollen ventrally. Copulatory 

 papillae absent in two specimens ; in the fully clitellate specimen there is a papilla on 

 segment 16 on the right side on the posterior border in setal line a, also swollen areas 

 without definite papillae ventrally on segments 16-18. 



Microscolex michaelseni, Bedd., hermitensis, subsp.n. (Fig. 2 a, b). 



St. 222, St Martin's Cove, Hermite Island, Cape Horn, 23. iv. 27, under logs and stones; three 

 mature specimens in very poor preservation (cotypes). 



Length (two uninjured specimens) 73 and 75 mm. Colour very slightly tinged with 

 red-brown pigment dorsally at the anterior end. 



Clitellum saddle-shaped, from about 14-16. Copulatory papillae apparently 

 absent, but the state of preservation does not permit certainty. Dorsal pores absent. 

 Intersetal ratios, aa : ab : be : cd : dd, at anterior end approximately 1-5 : i : 1-5 : 1-5 : 2, 

 dd= ca. \u; at posterior end, approximately, i\: \ : \ : \: 2, dd= ca. ^u. 



The gizzard, as far as the state of preservation allows determination, appears to be 

 quite absent. Salivary glands extend into segment 7 dorsally over the pharynx. Testes 

 and spermiducal funnels, only one pair, in segment 10; there was no trace of a rudi- 

 mentary second pair in 1 1 in any of the three specimens. 



Prostates occupying 3-5 segments each. The duct is long and somewhat coiled, thicker 

 near the external opening, thinner near the gland, from which it is sharply separated. 

 The duct occupies the first or first and second segments, the short, coiled, tubular gland 

 the remaining two or three segments. 



Penial setal sac muscles originate from the body wall at the first intersegment behind 

 their respective prostatic pores. 



Penial setae in two dissimilar sub-bundles. The setae of the two bundles are of 

 approximately the same length (0-9-1 -6 mm.) but those of the a bundle are more 

 slender than those of the b in any given specimen, although the range in diameter 

 actually overlaps (diameter near base, a ca. 20/x, b i8-5-2i-5/^; in middle of stem, 

 a 11-14/^, b 14-20 /i). In general form the setae are as figured by Michaelsen for the 

 types^ ; the setae of the a bundle taper very gradually, of the b bundle more rapidly to a 

 filiform point. The setae of the a bundle agree with Michaelsen's more slender type in 

 being ornamented at the distal end on the inner side of the curvature with prominent 

 serrate teeth, the tapering point beyond the region of large teeth being ornamented with 

 a few small irregular teeth or markings (Fig. 2 b). The setae of the b bundle differ from 



1 191 1. Michaelsen, W., Zool.Jahrb., Abt.f. Syst., xxx, p. 567, pi. 15, figs. 10 and 11. 



