INDIAN NUDIBRANCHIATE MOLLUSCA. 145 



Family HERM^ID^, Alder 8^ Hancock. 



Genus Phyllobranchus, nov. gen. 



Body elongate, flattened on the back, and angulated at the sides, without distinct 

 cloak. Tentacles two, dorsal, longitudinally folded, bifurcate above, non-retractile. 

 Head produced at the sides into angulated and folded expansions. Branchise leaf-like, 

 with distinct footstalks, arranged in several rows along the sides of the back and roand 

 the head in front. Anus lateral. 



The tongue of this genus resembles that of Hernusa. In our species there are thirty- 

 seven or thirty-eight short stout spines, in single longitudinal series, with seventeen or 

 eighteen truncated denticles on each side. The spines diminish rapidly in size in front, 

 where the tongue is convoluted. 



Phyllobranchus orientalis, Kelaart, sp. (Pi. XXXIII. figs. 18, 19.) 



Body elongated, but capable of great contraction, flattened on the back, and angu- 

 lated at the sides, of an olive-green colour. Dorsal tentacles placed much forward, 

 long, cylindrical, longitudinally folded through their entire length, and bifid above for 

 about one-third down : the slit is posterior ; the external surface has a few minute 

 tubercles. Branchiae large, ovate, leaf-like, with long footstalks, arranged in crowded 

 ill-defined rows along the sides of the back and round the head, extending backwards 

 nearly to the tail : the peduncles are cylindrical, the foliaceous portion flattened into 

 ovate laminae, with a minutely denticulated margin ; the upper surface is slightly con- 

 cave, and a little hollowed below, where the margin of the leaflet is raised at the top of 

 the peduncle ; its surface has four stout branched lines, radiating from the footstalk : 

 more minute radiating lines are seen on the under side : the hepatic gland forms a beau- 

 tiful dendritic expansion of a dark green colour, the stalk passing down the peduncle. 

 Head flat above, inclined downwards, and rounded in front ; produced at the side^ into 

 foliaceous expansions, which are angulated behind, and extended into folded tentacular 

 points. Foot dark olive, broad and ample, slightly arched and produced into blunt 

 points in front, where it is laminated but not notched; behind, it tapers to a blunt 

 point. There is a white spot on the back, with a slight swelling indicating the region 

 of the heart. Length 2^ inches. 



Proctonotus orientalis, Kel. in Journ. Asiatic Soc. (Ceylon Branch) 1858 ; idem, in 

 Ann. Nat. Hist. 3rd ser. vol. iii. p. 492. 



This curious animal is not uncommon. There are six or seven specimens in the 

 collection, but they are all too hard and brittle for anatomical examination. Mr. Elliot 

 informs us that the branchial papillae are very liable to fall off", and that their loss does 

 not seem to inconvenience the animal. It is occasionally found of a very pale green, 

 without any tinge of olive. The native name for it is Aku-purugu (leaf-animal). 



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