NoTT. — On N.Z. Comi)osite Ascidians. 311 



through a narrow pyloric constriction into the short much- 

 swollen intestine (fig. 7, i., and fig. 2,'p.h.). Through a second 

 constriction the rectum is reached : this in its earlier course 

 is largely dilated (fig. 7, r.) and glandular. It turns out of 

 the plane passing vertically through oesophagus, stomach, and 

 intestine slightly to the left, then recurves sharply as a trans- 

 parent membranous tube surrounding the dark faecal pellets 

 to the right side of the oesophagus, round which it passes 

 dorsally, and thence makes its exit through the oesophageal 

 constriction. The atrial pore is seemingly plain, showing 

 neither lobes nor languets (fig. 10, a.p). Glands are present 

 chiefly on the pyloric bulb of the stomach, where they have 

 the form of large homogeneous cells, strongly refractive and 

 giving the bulb a somewhat crenated appearance in its out- 

 line. 



Eeproduction appears to be effected chiefly by gemmation 

 of the type called " pyloric " (fig. 10). In all cases where 

 gemmation was observed the young zooid had exactly the 

 position with respect to its parent figured in Plate XXIV., 

 the dorsal surface of the former being apphed closely to the 

 ventral (endostylic) surface of the latter. 



The testis consists of a single large pyriform mass, granular 

 in appearance and deeply stained, surrounded at a varying 

 distance by a delicate trtT-nsparenb membrane. The " stalk " 

 of this mass connects with the vas deferens, which is strongly 

 defined, and coils eight or nine times around the membranous 

 testicular investment before springing up to pass through the 

 oesophagus (fig. 10, v.d.). 



A single large nucleated body, of opaque homogeneous ap- 

 pearance, lies near the intestine and testis in many zooids from 

 colonies obtained in September. These I take to be ova 

 (fig. 10, ov). 



Note. — All uotico of the peripharyngeal band is omitted in the above 

 account. It is present as a circlet o£ deeply-stained cells passing around 

 the thorax on its inner surface, between the buccal tentacles and the 

 branchial basket. Ventrally it unites with the commencement of the 

 endostyle, while dorsally it is hollowed to receive the nerve ganglion (fig. 

 i,pp.h.). This band is the point from which the mantle (epithelial and 

 connective-tissue layers) separate clearly from the body- wall ; the mantle- 

 ectoderm is represented by the lining of the test-cavity {m.e.). 



Leptoclinum densum, n. sp. Plate XXV. 



Colonies of large size were obtained on each visit for pur- 

 poses of collection. 



The corm is an incrusting mass varying in thickness from 

 l-2mm. to 4mm. In some cases the edge of a colony leaves 

 the object of attachment, and, growing freely for some time, 

 turns over upon itself, thus forming a double layer, reaching a 



