RUNCINA. 15 



Genus RUNCI'NA*, Forbes. PL I. f. 3. 



This genus being the only one known, it is unneces- 

 sary to repeat the description of the family. 



Runcixa HANcocKif, Forbes. 



Pelt a or Limapontia? sp., Alder & Hancock in Ann.& Mag. N. H. xxiii. 

 p. 289, pi. iv. f. 1-3. B. Hancocki, F. & H. iii. p. 012, pi. CCC. f. 2. 



Body smooth, more or less clothed with microscopic vibra- 

 tile cilia : mantle a little indented in front, nearly straight at 

 the sides, and slightly rounded behind : colour black, sprinkled 

 with minute points of brown, except at the front and rear, 

 which are buff and fawncoloured : eyes rather large, each 

 surrounded by a pale ring ; behind the eyes is a curved line 

 of small white specks : foot yellowish, tinged with brown or 

 black, and marked with a few flake-white spots ; it is rounded 

 in front, the sides are almost parallel and broader than the 

 mantle, towards which they are usually folded up ; tail or 

 extremity of the foot extended one-fourth of the length of 

 the body behind the vent : gill-plumes 3, small, slightly pin- 

 nate, near the vent, and generally projecting a little beyond 

 the mantle : vent beneath the posterior margin of the mantle 

 (Alder and Hancock). L. 0-2. B. 0-1. 



Habitat : On Confervse, in pools near high-water 

 mark, at Torquay (Alder and Hancock) ; Belmont Bay 

 near Weymouth (Thompson and Gray). Mr. W. 

 Thompson informs me that it is very abundant in rock- 

 pools at low-water of spring tides, among Confervse 

 (Ceramium strictum, C. rubrum, and C. Deslongchampii) , 

 apparently feeding on the Diatoms which swarm on 

 these delicate seaweeds. Clyde district in rock-pools, 

 with Limapontia nigra (Norman) . 



* A rural goddess. 



t Commemorative of Mr. Albany Hancock, whose labours on the 

 Nudibranehs, in conjunction with Mr. Alder, are especially famous. 



