HuTTON. — On the Fresh-water Lamellibranchs of Neiv Zealand. 149 



think, distinct, although some specimens are difficult to distinguish from 

 U. menziesii. I have not examined the animal. U. hochstetteri I have 

 never seen. 



Notes on the animal of U. menziesii. — PI. II., figs. A, b, c, and d. The 

 anal siphon is dark purple outside and yellow inside ; the orifice is simple. 

 The region of the branchial siphon has numerous cirri, some of which are 

 dark purple, others yellow; inside the shell the margin of the mantle is 

 speckled with yellow pigment spots. The branchi© are yellow-brown in 

 colour, the outer darker than the inner one. They are attached at their 

 posterior extremities to the mantle below the anal siphon, but are free from 

 this point to the posterior adductor. The outer branchia is attached to the 

 mantle throughout its whole length, and is obliquely truncated anteriorly ; 

 the inner branchia is not united to the foot. The foot is large, and its 

 anterior and lower portions, which are not covered by the branchiae, are 

 slate grey in colour. The labial palpi are white, speckled with yellow, their 

 length is about twice their breadth, and for about half their length the two 

 on each side are united posteriorly. All the nervous ganglia are white, but 

 show nothing remarkable in shape or position. The heart makes fifteen 

 beats a minute. The alimentary canal is remarkably simple ; from the 

 capacious stomach it runs along the lower side of the body cavity to the end, 

 and then turns abruptly upward and forward to the stomach, from whence 

 it ascends to the heart. A crystal-style is sometimes present. The animal 

 is dicEcious. I have found both spermatozoa and ova in the month of June. 



Cyeenid^. 



In the Catalogue of the " Conchifera in the British Museum," and in 

 the "Proceedings of the Zoological Society of London" for 1854, M. 

 Deshayes has described a Sphcsrium novce-zealandicB, which has been also 

 figured by Eeeve. It is a small species of a bluish-grey colour "abundantly 

 irregularly transversely banded ;" and is said to come from New Zealand 

 and Australia. I have never seen a shell answering to this description, 

 and the New Zealand habitat may perhaps be erroneous. 



In the " Malakozoologische Blatter" for 1861, Dr. Bunker described a 

 Sphcerimn lenticula from specimens brought to Europe by Dr. v. Hochstetter 

 from Lakes Eotoiti and Taupo. This little shell (pi. II., fig. e) is common 

 throughout New Zealand ; bub it is a Pisidiimi, and not a Sphcerium, 

 Usually it is nearly equilateral (fig. E.ff.), but occasionally very inequi- 

 lateral (e.6.). The two forms are, however, only varieties of one species, 

 as intermediate varieties completely connecting them are found in the same 

 locality. At least both forms and intermediate varieties live together near 

 Christchurch. The longer side of the shell is anterior. The siphons are 

 very short, and completely united, the margin is simple. The foot is long 



