14 THE AUSTRALIAN MUSEUM. 



In size and general shape this species recalls Ascidia men tula of 

 European seas, but that the body is more compact in this species, and 

 the atrial aperture is placed further forward. The branchial aperture 

 is very irregularly lobed in the test, but in the mantle there seem to be 

 about 12 lobes, an unusually large number for an Ascidia. The surface of 

 the test may have little scattered knobs, which gives an appearance like 

 that of Pliallusia mammillata. There is a deep groove with several 

 branches running down the middle of the right side (PL Asc. II., fig. 1.) 

 in all the specimens. This may be partly due to contraction on death. 



In specimen D (No. 12 of Museum labels), where the colour of the test 

 is very dark there is a great deal of pigment found, and there are little 

 black areas O5 to 1 mm. in diameter scattered irregularly over the 

 surface. Each of these has a non-pigmented brownish lighter spot in 

 its centre (see figs. 9 and 10.), while similar smaller spots or papillae are 

 scattered all over the surface both on the black areas and between them. 

 Each such papilla is the enlarged knob of a blood vessel. The test is in 

 all cases very vascular (fig. 3.) When the test, which averages about 

 5 mm. in thickness, is removed the body looks rather small. It is flat on 

 the right side and convex on the posterior part of the left side, where 

 the viscera form a projection. The siphons are well marked. The 

 large branchial is anterior and the atrial is about one-fifth of the length 

 of the body from the anterior end, and is directed dorsally (fig. 1). 



The thick walled branchial sac has a rough appearance internally, due 

 to the large papillae (fig. 2). It is not reduplicated at the posterior end, 

 and this forms an important point of difference between the present 

 species and Ph. mammillata, the type of the genus Phallusia, according to 

 Eoule's classification. On account, however, of a certain resemblance in 

 form, and also in the condition of the neural gland described below, to 

 that species, I have given the specific name i>liallnsioides. 



One of the most notable points about this species is the remarkable 

 condition of the neural or hypophysial gland. This organ is large and 

 extends from the dorsal tubercle anteriorly to the nerve ganglion 

 posteriorly (fig. 7). Its aperture on the dorsal tubercle into the branchial 

 sac is small and simple (fig. 5), but it has a large number of complicated 

 secondary openings on the surface which is directed towards the atrial 

 cavity (fig. 8). 



In the dark variety (specimen D) the gland is longer and narrower 

 behind the dorsal lamina than in the other specimens, but is otherwise 

 the same, and has many secondary openings. 



This adds another to the small number of remarkable Ascidians 



