284 DISCOVERY REPORTS 



Isodictya kerguelensis, var. simillima (Hentschel). 



Homoeodictya kerguelensis, var. simillima, Hentschel, 1914, p. 80, pi. vi, fig. 7. 

 Occurrence. St. WS 109; Falkland Islands, 145 m. 

 Distribution. Wilhelm Land. 



Isodictya setifer (Topsent). 



Desmacidon setifer, Topsent, 1901, p. 6; id., 1901, p. 17, pi. i, fig. 3, pi. iii, fig. 6; Desmacidon 

 spinigera, Kirkpatrick, 1907, p. 283 ; id., 1908, p. 39, pi. xix, fig. 3, pi. xxiii, fig. 3 ; Desmacidon 

 setifer, Topsent, 1908, p. 26; Homoeodictya verrucosa, id., 1913, p. 636, pi. v, fig. i, pi. vi, fig. 13 ; 

 H. setifera, id., loc. cit., p. 637; H. obliquidens, Hentschel, 1914, p. 79, pi. iv, fig. 7, pi. vi, fig. 6; 

 H. setifera, id., loc. cit., p. 81 ; H. setifera, Topsent, 1917, p. 65, pi. vi, fig. 12; //. trigona, id., 

 loc. cit., p. 66; Desmacidon spinigera, Brondsted, 1926, p. 3; Isodictya spinigera. Burton, 1929, 

 p. 424; /. verrucosa, id., loc. cit., p. 424. 



Occurrence. St. 39: South Georgia, 179-235 m.; St. 42: South Georgia, 120-20401.; St. 143: 

 South Georgia, 273 m.; St. 144: South Georgia, 155-178 m.; St. 148: South Georgia, 132-148 m.; 

 St. 149: South Georgia, 200-234 m.; St. 159: South Georgia, 160 m.; St. 160: Shag Rocks, 177 m.; 

 St. 175: South Shetlands, 200 m.; St. 190: Palmer Archipelago, 93-130 m.; St. WS 73 : Falkland 

 Islands, 121m.; St. WS77: Falkland Islands, iio-ii3m.; St. WS 80: Falkland Islands, 152- 

 156 m.; St. WS81: Falkland Islands, 81-82 m.; St. WS 83 : Falkland Islands, 137-12901.; St. 

 WS 88 : Falkland Islands, 96-1 27 m. ; St. WS 99 : Falkland Islands, 251-225 m. ; St. WS 109 : Falkland 

 Islands, 145 m.; St. WS 239: Falkland Islands, 196-193 m.; St. WS 243: Falkland Islands, 144- 

 141 m.; St. WS 246: Falkland Islands, 267-208 m.; St. WS 248: Falkland Islands, 210-242 m. 



Remarks. There are 32 specimens in the collection which belong, in my opinion, 

 to the same species, namely Isodictya setifer (Topsent). They all resemble each other 

 strongly externally, and have much the same appearance as that of the holotype of 

 Homoeodictya verrucosa, Topsent (19 13, pl.v, fig. i). The form is massive to lobose, often 

 stipitate. In spiculation they agree also in having a main skeleton of oxea and, for 

 microscleres, isochelae palmatae, which have the peculiarity that they are often contorted 

 and distorted and the palms are sometimes obliquely directed. This peculiarity of the 

 microscleres has been overlooked in many cases, as for example in Desmacidon spinigera, 

 Kirkpatrick, although Topsent and Hentschel drew attention to it in Desmacidon setifer 

 and Homoeodictya obliquidens respectively. The reason for this seems to be that the con- 

 tortion and distortion are most marked in the smaller spicules, that is in those least 

 easily seen, and will only be noticed if the microscleres are numerous and the eye 

 happens to catch one in an isolated position in the preparation lying in a particularly 

 favourable angle for examination. At all events, I have satisfied myself that such micro- 

 scleres are present in the type of Desmacidon spinigera, Kirkpatrick, and that they are 

 present in varying proportions in the specimens of the present collection. It often 

 happens, of course, that a particular individual may have a greater proportion of normal 

 chelae than abnormal, and were one not looking particularly for contorted or distorted 

 microscleres these would be completely overlooked. I have no doubt therefore that in 

 the types of Homoeodictya verrucosa, Topsent, and other species in the above list of 

 synonyms in which abnormal chelae have not been recorded, these same peculiar chelae 

 are present, though probably in small quantities. 



