BY H. LEIGHTON KESTEVEN. 291 



Alimentary canal. — The oesophageal aperture is situated 

 ^anteriorly almost directly beneath the atrial siphon, and close to 

 the branchial aperture; from here the gut passes posteriorly and 

 ventrally along the left side; sweeping round anteriorly again, it 

 turns abruptly back on its course and returns to its starting 

 point parallel and close to itself, so that the intestinal loop is very 

 narrow. There are no macroscopic features indicating the various 

 regions of the gut (Pl.xxvii., fig. 11). 



Hah. — Hobart Harbour, dredged 5-11 fathoms (A. Morton.) 



2'ype to be presented to the Australian Museum. 



The novelty is named for the late Mr. Alexander Morton, who 

 xjollected and presented it to me. 



This Molyula is of typical shape, but is atypical in the absence 

 of sand-grains and processes of the test, and also in being attached. 

 The branchial sac, in its regularity on the folds and rarity of 

 vortices, presents an intermediate condition towards Ascopera. 



Dendrodoa gregaria, sp.nov. 

 (Plates XXV., tigs. 1-3; xxvi., fig.7; xxvii., figs. 1-5). 



External appearance. — The shape is extremely variable. Botli 

 apertures are anteriorly situated, on more or less prominent 

 pustulose areas; both are four-lobed. The most prevalent form 

 is that repsesented in outline by figure 3, Plate xxvii., roughly 

 pyramidal, the apex being the branchial siphon; on the other 

 hand that contour may be turned upside down, as it were, as 

 represented by figure 4; other individuals are roughly quad- 

 rangular (fig. 1) or globular. The colour is dull grey in exposed 

 parts, du.'^ky tan round and between the siplions; and in specimens 

 growing in clusters, the contiguous portions are silvery white. 

 The resemblance between this species and Molgula mortoni is 

 very close, the latter differing only in being more globular. 



Tlie test, in macroscopic features, resembles that of M. mortoni, 

 differing only in being a little thicker. Test-cells are very 

 numerous, ovoid and fusiform, the former much the more abun- 

 dant; stellate cells are not present. Phagocytes (1) are also 



