156 Transactions.— 2 oolofi I/. 



and colourless. The animal is very active and moves about by means of 

 its foot, much in the manner of a Gastropod, It lives not only in mud, 

 but also on aquatic plants. 



Pisidmm novcB-zealandim was described by Prime in the " Proceedings of 

 the Zoological Society of London " for 1862, and afterwards in the " Annals 

 of the Lyceum of Natural History of New York" for 1867 with a wood-cut. 

 This may be the same as the variety h of PisicUum lenticida, as the descrip- 

 tion agrees very well ; but if so the figure, judging from a tracing I had 

 made for me, cannot be very correct, for that represents a nearly equilateral 

 shell with a prominent umbo. The specimens described by Mr. Prime are 

 said to have been brought from New Zealand by Mr. Cuming, so there may 

 be a mistake in the habitat, as I believe Mr. Cuming never visited New 

 Zealand. 



EXPLANATION OF PLATE II. 



A. Unio menziesii, with the foot expanded, c anal siphon. 



B. Unio menziesii, left valve and mantle removed, a Anterior adductor muscle ; 



b posterior adductor ; c anal siphon ; d foot ; e labial palp ; / branchiae. 



C. Unio menziesii, left side of mantle and branchiae removed, and the pericardium 



laid open, a Anterior adductor ; b posterior adductor ; d foot ; e labial 

 palp ; / right branchia ; g rectum ; h heart ; i cerebral ganglion ; k parieto- 

 splanchnic ganglia. 



D. Unio menziesii, body cavity laid open, showing the mouth, stomach and intes- 



tine ; I pedal ganglia. 



E. Pisidium lenticula. a Type form ; b variety. 



Art. XIX. — Notes on some Pulmonate Mollusca. 



By Professor F. W. Hutton. 



[Bead before the Philosophical Institute of Canterbury, 2nd June, 1881.] 



Plates III. and IV. 



Patula coma. Gray. The jaw is slightly arcuate, with the ends attenu- 

 ated ; it is marked with distant stride which converge slightly towards the 

 upper margin. (Plate III., fig. l.) 



The radula is '01 inch in breadth. Teeth 13-1-18, of which 6 may be 

 called laterals. The central tooth is tricuspid, the side cusps short and 

 rounded and without cutting points, the median cusp long and narrow with 

 a small cutting point at the extremity ; the base of attachment is broad and 

 rectangular, and extends beyond the cutting point of the median cusp. 

 The lateral teeth are similar to the central, but the base of attachment is 

 oblique. The seventh tooth has the cusps nearly equal, and the inner side 



