NoTT. — On N.Z. Composite Ascidians. 313 



"but show the same peculiar ossophageal constriction (fig. 7, 

 ce.c). The thorax is much smaller than in the preceding 

 form : the abdomen is nearly equal in size in each. 



The branchial siphon (fig. 5) is long and much dilated 

 above. Its edges exhibit six lobes of small size. The mantle- 

 ectoderm surrounding it shows very distinct nuclei. The 

 buccal tentacles are sixteen in number, and even in length ; 

 their ends being pointed. 



The branchial basket generally exhibits the same features 

 as L. nive2tm, except that everything is proportionately re- 

 duced owing to the smaller size of the thorax. 



The endostyle (fig. 5, ai.) is remarkable for the upward 

 extension of its pointed conical end above the muscular buccal 

 ring from which the tentacles hang. Its course is a recapitula- 

 tion in other respects of that of the previous species. The 

 dorsal lamina also offers no distinctive features. 



Nervous centres were frequently visible in many zooids as 

 opaque bodies situated on the dorsal body-surface (fig. 7, «.). 

 None were seen in transverse section. 



The peripharyngeal band (fig. 5, pp-h.) is clistinctly visible 

 below the circle of tentacles, its connection with the endostyle 

 being also distinct. The commencement of the peribranchial 

 cavity at this point is also very noticeable, though visible only 

 in zooids whose thorax has been longitudinally slit. 



The alimentary tract exhibits no traces of a pyloric bulb, 

 but a well-marked pyloric constriction divides the intestine 

 from the stomach. The rectum is not distinctly coiled round 

 the oesophagus as in L. niveum (fig. 7), but probably repeats 

 an analogous curvature nearer the oesophageal constriction. 

 The atrial pore is plain. 



No instances of gemmation were observed, but sexual 

 reproduction appears to be common, judging from the number 

 of tailed larvae present in the colonies found. 



A curious feature in the testis was observed in some three 

 or four cases, and may possibly be normal. The single vesicle 

 characteristic of the family appeared split in two. The in- 

 vesting membrane surrounds both the closely-applied masses 

 (fig. 8), and the vas deferens coils spirally around it some 

 seven or eight times. The testis is near the intestinal loop, 

 and usually on its right side (fig. 7). 



Hard by the testis opaque bodies distinctly nucleated were 

 observed in all colonies, greatly resembling those found in 

 L. niveum. Only one was present in each zooid where they 

 were found, and from many they are absent altogether. 

 Similar bodies are present in the lower layer of the test in 

 considerable numbers (fig. 9, ov.). They are of large dimen- 

 sions, being often nearly equal to the testis in size (fig. 7, v.d. 

 and ov. ; and fig. 8, ov.). 



