CATALOGUE OF TUNIC AT A. 49 



marked by creases, especially at dorsal edge and posterior end. Covered 

 with particles of sand and shells. Colour greyish brown. Length 9 cm., 

 breadth 4 cm., thickness 1-5 cm. 



Test leathery, thin but tough, slightly stiffened by sand grains ; inner 

 surface smooth and glistening. 



Mantle does not adhere to test ; yellow, opaque, but with musculature 

 feeble. No distinct muscle bands visible. 



Branchial sac has 4 folds on each side. Transverse vessels wide 

 and of 3 sizes. There are 6 to 8 internal longitudinal bars seen on 

 each fold, and 4 or 5 in the interspaces. The meshes are elongated 

 transversely ; they contain each 5 or 6 stigmata. Horizontal membranes 

 are very slight, and the meshes are not divided. 



Dorsal lamina is a narrow and plain edged membrane. 



Tentacles about 48 in number, of 3 sizes, arranged symmetrically ; 6 

 longer, 6 medium, and about 36 shorter. 



Dorsal tubercle large and somewhat horse-shoe shaped. Left horn 

 coiled inwards ; right horn not coiled but turned outwards. 



Gonads in the form of many small polycarps, imbedded in the thick- 

 ness of the mantle. 



Locality. Port Jackson ; one specimen. 



This large and rather sandy species (PL Cyn. XIX., fig. 1) resembles 

 Polycarpa longisiphonica in external characters, but differs in the non- 

 adherence of mantle to test, in the arrangement of transverse vessels in 

 the branchial sac, in the number and arrangement of tentacles, and in 

 the shape of dorsal tubercle. 



Although there is a good deal of sand on the test, it is not so much 

 imbedded as to render the test brittle, as in Polycarpa Sluiteri. 



The mantle is moderately thick, but there are no large muscle 

 bands. The polycarps are very slightly developed, and are entirely sunk 

 in the mantle. The stigmata are rather small (fig. 2), so as to leave 

 rather wide transverse vessels. 



The tentacles (fig. 4) are all rather small, and the larger ones are 

 very few. The minute intermediate ones are always 3 together. The 

 dorsal tubercle (fig. 3) has a very wide pre-branchial zone separating it 

 from the tentacles. 



Polycarpa longisiphonica, Herdman, PI. Cyn. XIX., figs. 5, 6. 



This is one of the species found by the "Challenger" Expedition at 

 Port Jackson, and I now refer to it a specimen in the present collec- 

 tion labelled "Port Stephen, 25 to 30 faths., and agreeing in all 



