A MONOGRAPH OF THE 



Fam. 2. Polycerida. 

 Section 1. Tentacles non-retractile. 

 Gen. 6. Goniodoris, For. Body depressed; cloak distinct, with a waved or 

 scalloped margin ; dorsal tentacles laminated ; oral tentacles 

 flattened ; branchiae non-retractile. Tongue narrow, with 

 4 plates, the two next the median line bearing each a large 

 spine; no central plate. A spinous buccal collar 

 Gen. 7. Idalia, Leuck. Body convex, smooth ; cloak very small and indis- 

 tinct, margined with filaments, longest in front of the tentacles ; 

 head much produced in front, plain, thick ; tentacles 2, dorsal, 

 linear, laminated; branchiae simply pinnate, non-retractile. 

 Tongue narrow, with 4 spines, the 2 next the median line large ; 

 no central spine. A spinous buccal collar. 



a. Centre of the back with filaments. Lingual spines next 

 the centre falcate, and smooth or minutely denticulated ; 

 external spines short. Spinous collar complete 



b. Centre of the back without filaments. Lingual spines 

 next the centre recurved and strongly denticulated ; external 

 spines much hooked. Spinous collar incomplete, bilobed 



Gen. 8. Ancula, Loven. Body limaciform, smooth; cloak obsolete, form- 

 ing an indistinct ridge near the gills bearing several appen- 

 dages ; tentacles 2, clavate, laminated, non-retractile, with 

 styliform basal appendages ; head produced at the sides into 

 tentacular processes ; branchiae non-retractile. Tongue narrow, 

 with 4 spines, the 2 next the median line large and broad, with 

 the inner margin denticulated ; no central spine. A spinous 

 buccal collar ... 



Gen. 9. Polycera, Cuv. Body limaciform ; cloak indistinct, forming a 

 digitated veil and a ridge bearing a row of tubercles on each 

 side of the back ; tentacles 2, laminated ; branchial plumes 

 non-retractile, with lateral appendages. Tongue rather narrow, 

 with 12 to 16 plates, the 2 next the centre on each side large, 

 bicuspid ; no central plate. Lateral corneous jaws. 



a. Veil dilated into tentacular filaments ; branchial plumes 

 simply pinnate ; branchial appendages linear, one on each 

 side . . 



b. Veil short, bilobed, margin tuberculated ; branchial 

 plumes branched ; branchial appendages tubercular, more 

 than one on each side 



G. nodosa, Mont. 



I. elegans, Leuck. 



I. aspersa, A. & H. 



A. cristata, Aid. 



P. quadrilineata, Mull. 



P. ocellata, A. & H. 



Section 2. Tentacles retractile within sheaths. 



Gen. 10. Thecacera, Flem. Body limaciform, smooth; cloak obsolete; 

 veil indistinct, or none ; tentacles 2, laminated ; branchial 

 plumes n on- retractile, with lateral appendages. ( Tongue with 

 12 or 14 plates, the 2 inner plates on each side bearing bicuspid 

 spines; no central plate. Small lateral corneous jaws 



T. penuigera, Mont. 



