BRITISH NUDIBRANCHIATE MOLLUSCA. 



xxm 



Gen. 41. Tergipes, Cuv. Body slender; tentacles simple, the oral pair 

 very short ; branchiae fusiform, inflated, set in single series on 

 each side of the back ; foot narrow ; anterior angles rounded. 

 Spawn reniform. Tongue, a single plate with a stout central 

 spine and delicate marginal denticles 



Gen. 42. Embletonia, A. and H. Body slender; dorsal tentacles simple; 

 oral pair flattened into 2 lateral lobes ; branchiae fusiform, set 

 iu single or double series on each side. Tongue, a single plate 

 bearing a central spine and lateral denticles 



TYPE. 



T. despecta, Johns. 



E. pulchra, A. & H. 



Section 2. With two posterior lateral gastro-hepatic vessels ; reproductive organs with two 



external orifices. 



Fara. 13. Fionidce. 



Gen. 43. Fiona, A. and H. Tentacles sub-dorsal; branchial papillae with 

 an undulated membranous border set on a sub-pallial margin. 

 Tongue, a single plate with a stout central spine and marginal 



denticles 



Fam. 14. Hermcddcs. 



Gen. 44. Herm^ea, Lov. Tentacles 2, dorsal, longitudinally folded ; branchiae 

 fusiform or linear ; anus in front of the heart. Tongue, a single 

 plate bearing a large broad spine. 



a. Tentacles with both margins terminating at the sides of 

 the head ; body cylindrical 



b. Tentacles with the anterior margin continuous with the 

 sides of the head, forming a sub-veil ; body with the sides 

 depressed and slightly expanded 



Gen. 45. Stiliger, Ehr. (Calliopaea, D'Orb.) Tentacles 2, dorsal, simple; 

 branchiae fusiform, arranged in transverse rows on the sides 

 of the back ; anus in front of the heart. Tongue, a single 

 spine plate bearing a stout 



Gen. 46. Alderia, Allm. Tentacles rudimentary or none ; branchiae papil- 

 lose, set in transverse rows on the sides of the back ; anus pos- 

 tero-dorsal. Tongue, a single plate with a large central spine 



F. nobilis, A. & H. 



H. bifida, Mont. 



H. dendritica, A. & H. 



S. ornatus, Ehr. 



A. modesta, Lov. 



Sub-Order — Pellibranchiata. 



Tribe 1. Body limaciform. 



Fam. 15. Mysiadce. 



Gen. 47. Elysia, Risso. Tentacles 2, longitudinally folded ; lateral expan- 

 sions large, plain, meeting behind and folding over the back. 

 Tongue, a single plate with a large central spine. A spinous 

 buccal collar .... 



E: viridis, Mont. 



