COLLECTED BY THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 451 



transverse fibres consisting of a single stylus or of a bundle of a few styli. Spongin 

 is present in rather scanty quantities, and is best seen at the points where the 

 transverse fibres join the main ones. There is no special dermal skeleton. 



Spicules. — (l) Styli, with a slightly curved shaft. They vary in length between 

 0'2-0"26 mm., but are usually 0"23-0'25 mm. long. Their thickness is 0"008-0'01 mm. 

 (2) Isochelee palmatse are scattered throughout the sponge and in the dermal 

 membrane. They are 0'024-0'027 mm. in length by about 0'008 mm. across the tooth. 

 The axis is curved back from the inner side of the tooth, and its end shows as a 

 tubercle in front view, as described by Lundbeck (13) for a sponge recorded by him 

 under the name E. sp. (? alderi Bowerbank). This structure cannot be made out 

 in all the chelse. 



In the arrangement of the skeleton and in the size and shape of the megascleres, 

 this species is very like Esperiopsis fucorum (Johnston). It differs from the older 

 species in the larger size and, more particularly, in the structure of the isochelse. 

 It agrees with the Ingolf specimen mentioned above as regards the size and shape 

 of the isochelse, but differs from that sponge in possessing much shorter styli. 



Homceodictya compressa (Esper). (Plate XXXIX, fig. 4 ; Plate XL, fig. 12.) 



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

 specimens. 



One of the specimens of Homceodictya in the Scotia collection resembled Esper's 

 figure (7, pi. lv) of the sponge named by him Spongia compressa very closely in 

 external appearance, and its structure agreed so well with Ehlers' (6) short description 

 of the same specimen, that efforts were made to gain further information about the 

 type-specimen. Finally, a fragment of the original specimen was obtained through 

 the kindness of Dr C. Zimmer of the Zoological Museum, Alte Akademie, Munich, 

 in whose charge is the Esper collection of sponges. An examination of this 

 fragment showed that the arrangement of the skeleton and the size and character 

 of the spicules agree exactly in both sponges. 



Two specimens of this species are in the collection. The larger closely resembles 

 in shape, and in size and arrangement of the oscula, the figure given by Esper. 

 The Scotia specimen consists of a thick stalk, 30 mm. in diameter, which 

 spreads out into a broad compressed lobe, 105 mm. in greatest breadth and 

 about 30 mm. thick. The sponge, which is broken off from its support, is 

 175 mm. high. 



The whole surface, including that of the stalk, is covered with closely set tufts 

 of spicules, about 2 mm. in length, formed by the projecting ends of the main 

 skeletal fibres. One surface of the sponge is even, but the opposite side, towards the 

 summit, is raised into a prominent ridge running across the broadest part of the 

 sponge. The oscula are found along the margin of the sponge and on the summit 



