TETRAXONIDA 267 



Occurrence. St. WS 27 : South Georgia, 106-109 m. ; St. WS 83 : Falkland Islands, 137-129 m. ; 

 St. WS 86: Falkland Islands, 151-147 m.; St. WS 87: Falkland Islands, 96-127 m.; St. WS 99: 

 Falkland Islands, 251-225 m.; St. WS 243: Falkland Islands, 144-141 m.; St. WS 247: Falkland 

 Islands, 172 m. 



Diagnosis. Sponge tubular, infundibular or bilamellate; texture elastic, very 

 soft, somewhat friable ; outer surface minutely hispid, shaggj^ often thrown into irregular 

 folds; inner surface even, minutely hispid, bearing numerous exhalant apertures 

 varying up to 3 mm. in diameter; colour, in spirit, greenish yellow or brown; skeleton 

 a regular isodictyal reticulation with bi- to trispicular primary fibres connected by trans- 

 verse single spicules at regular intervals; oxea measuring o-i6 by 0-007 ""'""'• 



Remarks. The holotype (Plate XLVIII, figs. 5, 6) is an incomplete sponge, 

 apparently infundibular in life, bearing a strong resemblance to Calyx (Gellius) 

 imperialis (Dendy)i from New Zealand, with which at first sight it might be easily 

 confused. All the remaining specimens are damaged, though some only to a slight 

 extent, and they vary from tubular to bilamellate. 



The characteristic feature of the species is the external form. In many respects this is 

 like that of H. {Reniera) Scotti (Kirkpatrick), but the sizes of the respective spicules differ 

 too much to allow of a specific identity at the moment. 



There are a number of other specimens which, in spite of the differences in external 

 form, appear to belong to the same species. All have the same soft, friable texture, the 

 same appearance and a very similar type of skeleton. The diversity in external form 

 exhibited by them furnishes a good example of the extent to which the Chalinine sponges 

 may vary. 



The external form of these specimens is as follows : 



Specimen i. More or less pyriform with a deep cloaca, the walls of which are marked 

 with large exhalant apertures. Surface minutely conulose. Colour dark brown 

 (Fig. 6 a). 



Specimen 2. Stipitate and tubular, with deep cloaca, the walls of which are marked 

 with large exhalant apertures. Surface markedly conulose, particularly near the top of 

 the sponge. Colour dark brown (Fig. 6 b). 



Specimen 3. Sponge tubular in the lower two-thirds, infundibuliform above. Surface 

 of lower two-thirds with long, slender spinose processes. Colour dark brown 



(Fig. 6 c). 



Specimen 4. Sponge tubular. Surface covered with spinose processes (Plate XLIX, 



fig. I). 



Specimen 5. Sponge tubular. Surface covered with low, rounded, irregular ridges 

 (rather like Haliclona dancoi (Topsent) in appearance). Colour yellow (Plate XLVIII, 



fig- 9)- 



1 Gellius imperialis, Dendy, is a typical Calyx, differing from C. arcuarius (Topsent), described on page 277, 

 in its external form and in the substitution of sigmata for toxa. In all other respects the two species are 

 practically identical. 



