92 



DISCOVERY REPORTS 



Family AGNESIIDAE Huntsman, 1912 



Genus Agnesia Michaelsen, 1898 



Agnesia glaciata Michaelsen (Text-fig. 30) 



Agnesia glaciata Michaelsen 1898, p. 370. 



Agnesia krausei Michaelsen, 1912, p. 181, figs. 24, 25. 



Agnesia capensis Millar, 1955, p. 191, fig. 19. 



Occurrence. St. 91 : False Bay, S. Africa, 35 m. St. 939: N. Island, New Zealand, 87 m. St. WS 

 775: Patagonian Shelf, 115-uom. 



External appearance. The two specimens from the Patagonian Shelf have lengths of 17 and 10 mm. 

 The single specimen from False Bay, South Africa, is 9 mm. long and the largest of those from north 

 of New Zealand is 12 mm. long. In most cases the body is rectangular in outline. In all specimens 

 the test is thin and very transparent, but is hidden to a variable degree by the sand or broken shell 



2.0 cm 



3.0 cm 



Text-fig. 29. Ascidia sydneiensis Stimpson (St. 1686): A, external appearance of specimen; 



B, same specimen with test removed. 



which adheres to it. This coating of sand is most complete in the specimens from New Zealand and 

 least in those from the Patagonian Shelf. Test hairs are sparsely developed in the specimens from the 

 Patagonian Shelf and South Africa, but appear to be absent in the New Zealand specimens. 



Musculature (Text-fig. 30A). The same arrangement of muscles is found in all the specimens, 

 but the degree of development varies. Longitudinal muscles radiate out from the two siphons and 

 pass downwards across the upper part of the body. Strong circular muscles are present on both 

 siphons, round which they form complete rings. Posterior to the siphons the circular muscles are 

 represented by four longitudinal series of short transverse bands (t.m.), one series near the dorsal and 

 one near the ventral margin of each side of the body. When the body is contracted these short trans- 

 verse bands are inconspicuous, and this may possibly account for the omission of any reference to 

 them by Michaelsen (1898, 1900) in his descriptions of A. glaciata and A. krausei. 



Remarks. A. glaciata, the type species of the genus, was found off Tierra del Fuego and described 

 by Michaelsen (1898, 1900); he subsequently described another species, A. krausei, from the Pata- 

 gonian Shelf. A single specimen from Table Bay, South Africa, was made the type of a third species, 



