308 Transactions. — Zoology. 



my species will in all cases be found to be new, as I have had 

 no access to most of the works dealing wdth the subject. 

 Such as I have had, however, lead me to conclude that our 

 New Zealand forms are all peculiar ; but of this more must be 

 said later on. Of general works on zoology, such authors as 

 Eolleston ("Forms of Animal Life"), Huxley ("x\natomy of 

 Invertebrata"), Claus ("Zoology"), were all that I "had to 

 depend upon : very little could, however, be derived from 

 thence. More important in every sense are the papers by 

 Professor Herdman on the Tuuicata found during the 

 "Challenger" expedition (vol. vi., pt. xvii., and vol. xiv., 

 pt. xxxviii.). The latter deals, on the whole, exhaustively 

 with the "Challenger" species, though incomplete in some 

 particulars, and is of still higher value on account of the 

 amount of information it affords with regard to general anato- 

 mical details and to classification. The latter, especially to 

 a beginner, presents features of very great difficulty, and I 

 must here premise that my nomenclature is merely j)rovisional, 

 being designed rather to serve as a convenience for reference 

 than to remain unchallenged in the scientific world. 



Three distinct genera are represented in the North Shore 

 forms, their generic affinity being quite beyond doubt. The 

 genus Cystodytes, von Drasche, is represented by two forms, 

 W'hich, added to the live known species, gives a total of seven. 

 Herdman places this genus among the Distomidas. Four 

 New Zealand species are referable to Milne-Edwards's genus 

 Leptoclinum, as also are a number of varieties, thus further 

 extending this large family in distribution, if not in number of 

 species. Lastly, two closely-allied but quite peculiar forms are 

 found, which I place provisionally in a new genus, Pohjsyncra- 

 ton. As to the family relationship of the latter genus, I may 

 here remark that it is the most interesting point offered for 

 consideration by our Composite Ascidians : further discussion 

 may be postponed till their description is completed. 



Paet II. — Anatomical and Histological. 

 Family DIDEMNID^. 

 Genus Leptoclinum, Milne-Edwards. 

 Leptoclinum niveum, n. sp. Plate XXIV. 



Small colonies of this form were obtained both in July and 

 September. 



The colony is usually of small extent, the thickness varying 

 from 1mm. to 2mm., and closely incrusts the loose stones 

 lying about the reef, being met with only on the under-surface. 

 It is readily distinguishable from the other three New Zealand 

 species by its pure dense-white colour and uniform texture of 

 surface. The position of the zooids can only faintly be recog- 



