120 THE PROCEEDINGS OF THE LINNEAK SOCIETY 



EXPLANATION OF FIGURES. 

 Plate 12. 

 Fig. 2, 2a, Helix atramentaria, for comparison with fig. 3, 3a, 

 Helicarion fumosa — both natural size. 



Fig. 5, 5a, Helix imicoidee, much enlarged. 



On a new genus of Poltzoa. PL 13, fig., 1, la, lb, Ic. 

 By the Rev. J. E. Tenison-Woods, F.L.S., &c. 



The very interesting and curious genus which I now describe 

 was dredged by the Hon. Wm. Macleay, P.L.S., ofiP Darnley 

 Island, at a depth of 10 or 20 fathoms, on coral mud. It belongs 

 to the Cheilostomatous sub-order, but differs so completely from 

 any of the described families that its affinities and relations must 

 remain problematical until others are discovered, as no doubt in 

 time there will be. The nearest family is the Selenariadce, which 

 has the polyzoary more or less orbicular, convex on one side, 

 but there is no special modification of any organ in the manner 

 seen in the species under consideration. Its singular beauty, 

 both as regards design and ornament, renders it a remarkable 

 addition to an order where beauty and variety are the rule. I 

 shall distinguish the genus by the name Euktimenaria, from 

 evKTifJievo<i, well built. 



Edktimenaria, new genus. 



Polyzoary free, upper surface convex, covered with cells ; 

 lower surface divided into five portions, each containing large 

 pores ; in the centre of the base a vermiculate quinque-partite 

 body. 



Euktimenaria ducalis. PI. 13, fig. 1, la, lb, Ic. 



Convex, with pentagonal outline ; the edge circumscribed by a 

 raised margin of five arches, whence it descends to a broad 

 pentagonal pedicel by five arched concave surfaces, which are 

 horizontally divided in the centre by a straight raised double 

 ridge, above and below the centre of which there is a large 

 conspicuous pore ; the pore above is semi- circular, that below iis 



