COLLECTED BY THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 459 



are 0'06-0'l mm. in diameter, and are placed about 0'2-0'4 mm. apart. The main 

 fibres are connected by transverse fibres perpendicular to them, which join one main 

 fibre to the next, but which do not themselves form continuous fibres. Thus a 

 more or less rectangular network is formed. The transverse fibres are usually 

 between 0'05 and 0'07 mm. thick. In them the oxea are arranged in two, three, 

 or more rows, and are surrounded by a thick spongin sheath. There is no 

 special dermal skeleton. 



Spicules. — Oxea, 0"11-0'14 mm. in length by 0*013 mm. The most usual length 

 is 0'125— 0'13 mm. They thus agree with Ehlers' measurements of the oxea of the 

 type-specimen. Some of the small specimens have, on the whole, very slightly 

 longer oxea reaching up to 0'15 mm. in length. 



Siphonochalina anonyma n. sp. (Plate XXXIX, fig. 6 ; Plate XL, fig. 9.) 



Station 483. Entrance to Saldanha Bay, 25 fathoms. 21st May 1904. Four 

 specimens. 



The largest specimen consists of a stem, 10 mm. in diameter, rising into a long 

 tube, 22 mm. in width. About half-way up this tube two others are given off, one 

 of which is coalescent with the main tube for nearly the whole of its length. At the 

 base of the main tube, at the opposite side, a branch is given off nearly at right 

 angles, which bears three oscular tubes. The height of the specimen is 120 mm. 

 A second specimen is 85 mm. in height, and consists of a short stem, 8 mm. in 

 diameter, from which rises several tubes coalescing for nearly the whole of their 

 length. The whole sponge is 56 mm. in width. A third specimen is an unbranched 

 tube, 140 mm. in height by 19 mm. in diameter. It shows some slightly marked 

 swellings along its length. Near the base is a small rounded knob which seems to 

 be the beginning of a branch. The remaining specimen is very small, being only 

 23 mm. in height by 6'5 mm. It consists of a single tube with an osculum 1 mm. in 

 diameter at its summit. It is growing on a Polyzoan in company with many young 

 specimens of Homceodictya multiformis n. sp., some of which it resembles closely in 

 external appearance, but it is softer and more compressible in texture than these, 

 and the surface is more strongly hispid. 



The colour in spirit of all the specimens is pale greyish yellow. The sponge is 

 rather soft to the touch and compressible. The surface is even, but is finely hispid 

 from the projecting ends of the main skeletal fibres. The oscula in the large speci- 

 mens vary between 4 and 8 mm. The dermal membrane is thin, and the pores are 

 scattered and about '03-0 '075 mm. in diameter. 



Numerous embryos in different stages of development occur in two of the speci- 

 mens. They are about 0'2-0'3 mm. in diameter. The older embryos are crowded 

 with slender oxea. 



The main skeleton consists of fibres which run upwards and outwards from the 



