60 DISCOVERY REPORTS 



supplied by Kramp, I am satisfied that these ridges are present, though not well marked. In all three 

 species the place of attachment to the muscular lamella is deeply sunk, as Kramp says, in a narrow 

 longitudinal furrow. The lateral radial canals follow a straight course to the ring canal. There is 

 a ventral, medianly cleft mouth-plate. Whilst in 'S.' orthocanna, and in its antarctic counterpart men- 

 tioned on p. 59, the proximal side of the nectosac, bearing the junction of the canals, is free of muscular 

 tissue, in orthocannoid.es it is not so, nor is the wall of the nectosac of Marrus orthocannoides sunken 

 in as it is in those two species. 



Cbr 



-rS.mm 



Text-fig. 23. Alarms orthocannoides sp.n. A, fully grown; B, C, young bracts, x 10. The pecked portion 

 of the bracteal canal indicates the area of attachment of the bracteal muscle. 



Bracts. In a row ( ? rows) flanking the palpons, thin and leaf-like, the largest about 1 5 x 8 mm., 

 ovate, without marginal teeth. There are signs of thickened oblique truncate distal ends. The bracts' 

 attachment to the muscular lamella takes place along the proximal two-thirds of its length, so that 

 the terminal canal measures about one-third of the bract length. This canal appears to terminate in the 

 middle of one margin of the end-facet, without any sign of a pit or other surface marking. All the 

 bracts are detached. 



Palpons. Very numerous, slender, 9-2 mm. long x 0-2 mm., on short pedicels, close set in four to 

 five longitudinal rows, each with a fine tentacle. 



Gonodendra. Fine, about 4-6 mm. long, two or three per segment of stem, bearing a dozen or more 

 male gonophores on very short pedicels. The gonophores are globular, the largest measures i-i mm. 

 in diameter. As the gonophores of Marrus antarcticus were all female, it appears that Marrus may 

 be dioecious. 



