TETRAXONIDA 303 



Tedania massa, Ridley and Dendy (Fig. 25). 



T. massa, Ridley and Dcndy, 1886, p. 335; id., loc. cit., i886, p. 53, pi. xi, fig. 4, pi. xxiii, 

 fig. 2; Paratedania tarantula. Burton, 1929, p. 441. (For further synonymy see Burton, 

 loc. cit.) 



Occurrence. St. 42: South Georgia, 120-20401.; St. 148: South Georgia, 132-148 m. ; St. 152 

 South Georgia, 245 m.; St. 156: South Georgia, 200-236 m.; St. 158: South Georgia, 401-411 m. 

 St. 159: South Georgia, 160 m.; St. 160: Shag Rocks, 177 m.; St. 175: South Shetlands, 200 m. 

 St. 180: Palmer Archipelago, 160-330 m.; St. iSi : Palmer Archipelago, 160-335 m.; St. WS 80 

 Falkland Islands, 152-156 m.; St. WS 81 : Falkland Islands, 81-82 m.; St. WS82: Falkland 

 Islands, 140-144 m.; St. WS 83: Falkland Islands, 137-129 m. ; St. WS 87: Falkland Islands, 96- 

 127 m.; St. WS88: Falkland Islands, 96-127 m.; St. WS 93 : Falkland Islands, 133-130 m.; 

 St. WS 109: Falkland Islands, 145 m.; St. WS 216: Falkland Islands, 219-133 m.; St. WS 225: 

 Falkland Islands, 161-162 m.; St. WS 231 : Falkland Islands, 167-159 m.; St. WS 243: Falkland 

 Islands, 144-141 m.; St. WS244: Falkland Islands, 253-247 m. ; St. WS246: Falkland Islands, 

 267-208 m.; St. WS 248: Falkland Islands, 210-242 m.; St. WS 250: Falkland Islands, 251- 

 313 m. 



Remarks. Topsent (1917, p. 59), in recording Tedania chorcoti for the third time, 

 included under this name four specimens having the same spiculation as the holotype of 

 the species but possessing a pecuHar external form combined with a chitinoid ectosome 

 and a dermal tangential reticulation of styli instead of the brushes of tornota set at right 

 angles to the surface. Later, I established the synonymy of these specimens with 

 Oceanapia tarantula (Kirkpatrick) and removed the species to Paratedania. More 

 specimens have come to hand in the present collection, and in the light of these it is 

 clear that Topsent's action in treating this form as a simple variety of T. charcoti 

 was nearer the truth than I had thought. In one jar, for example, there are five 

 specimens. The largest is sub-spherical, about 1 1 cm. in greatest diameter, and dilTers 

 in no obvious respect from the rounded specimens of T. charcoti described by Topsent 

 (1913, p. 630, pi. v, figs. 3, 7). The same may be said of the smallest. A third specimen 

 (Fig. 25 a) is fixed to a fragment of shell, and around the base of the sponge runs a 

 narrow belt of chitinoid ectosome, the rest of the sponge being no different apparently 

 from the first and second specimens. This chitinoid substance is also secreted around a 

 portion of the shell. In a fourth specimen the chitinoid belt is wider, and just above it is 

 an ill-defined, discontinuous pore area (Fig. 25 V). The upper part of the sponge, not 

 covered with chitinoid ectosome, is again indistinguishable from the spherical form of 

 T. charcoti. In the fifth (Fig. 25 c) specimen, the chitinoid covering is more extensive. 

 The only difl^erences from T. charcoti observed in these specimens, apart from the 

 chitinoid ectosome, are (i) that the ends of the tornata tend to be more irregular and 

 occasionally slightly spined; (2) the oscules tend to become papillate as the chitinoid 

 ectosome increases; (3) beneath this special ectosome the brushes of tornota are lost 

 and the dermal skeleton is composed of a tangential reticulation of styli (which may 

 sometimes be modified to strongyla) ; (4) some, at least, of the pores become grouped into 

 a meridional pore area ; (5) the onychaeta are more liable to bear a swelling near one end 

 (= tylorhaphides of Dendy). Typical specimens of Paratedania tarantula merely show 



9-2 



