3o8 DISCOVERY REPORTS 



are in addition three specimens with skeletons somewhat intermediate in character be- 

 tween those of these two groups. In external form the specimens of each group show the 

 same variations ; from massive with digitate or flabellate processes, to massive, with the 

 surface raised into low rounded prominences, and, in rare cases, sub-clathrate. Further, 

 all the five specimens of the first group are from St. WS 27 (South Georgia, 106-9 ™- 

 depth) and four of the second group are from the same locality. The remaining speci- 

 mens of group 2 are also from South Georgia, from depths varying between 132 and 

 411 m. The similarity in external form between the members of the two groups, the 

 presence of intermediates as regards skeleton structure, and the similarity between the 

 two groups in spiculation, except for size of spicules and numbers present, suggest that 

 there is no taxonomic significance in this sub-division. Similarly, since all the specimens 

 from the first, and a third of the specimens from the second group are from the same 

 station, an ecological significance is hardly a possibility. It is, however, remarkable that 

 seven specimens of group 2, out of a total of eleven, contain embryos while none of the 

 specimens of group i has any. Possibly the looseness of the skeleton may have something 

 to do with the development of the embryos, and we may therefore accept all nineteen as 

 conspecific. 



Several of the specimens of this group are almost identical with the co-type of Tedania 

 charcoti, Topsent (1908, pi. iii, fig. 3). One or two of them approximate fairly closely 

 to the holotype {id., he. cit., pi. i, fig. 3), and there are several which difi"er slightly 

 from both. There can, however, be little doubt that all belong to T. charcoti. Here, 

 however, another point arises: Topsent (1908) records only two sorts of onychaeta in 

 his specimens, but in the present specimens exceptions are found to this. In the types 

 of this species, these spicules measure o-09-o-i2 and o-25-o-265 mm, long. In eleven 

 of the present specimens three sizes of onychaeta were found, the smallest measuring 

 from 0-05 to 0-105 mm., with an average of 0-08 mm., the largest, 0-24-0-32 mm., 

 with an average of 0-29 mm. Intermediate sizes were found, admittedly rare, 

 varying from 0-105 to 0-24 mm., with an average of 0-163 "^rn. In six specimens, 

 no intermediates were found, but in two specimens four separate categories appeared 

 to be present. Moreover, in some specimens the onychaeta were rare, in others com- 

 monly present, and in rare cases so abundant that they formed the bulk of the skeleton. 

 It does not seem possible therefore to use the onychaeta for the determination of species. 



Distribution. Graham Land; Burdwood Bank. 



Tedania murdochi, Topsent. 



T. murdochi, Topsent, 1913, p. 629, pi. v, fig. 5. 

 Occurrence. St, 53 : Falkland Islands, 0-2 m. 



Remarks. The typical form of T. murdochi, Topsent (1913, pi. v, fig, 5), is massive, 

 with mammiform lobes bearing oscules at their summits. The surface is usually 

 wrinkled, and in the present specimens has somewhat the appearance presented by the 

 holotype of T. charcoti, Topsent (19 13, pi. i, fig. 3). The colour is deeper than in the 



