330 MANUAL OF THE MOLLUSCA. 



GoNiODOEis, Forbes. 



Etymology, gonia, an angle. 



Type, G. nodosa, PI. XIII., Fig. 2. 



Animal oblong ; tentacles clavate, laminated, non-retractile ; 

 mantle small, simple, exposing the head and foot. Spawn 

 coiled irregularly. 



Distribution, 26 species. Norway, Britain (2 species), Medi- 

 terranean, China. Between tide-marks. 



Tmopa, Johnston. 



Tijpe, T. claviger, PL XIIL, Fig. 3. 



Synonym, Psiloceros, Menke. 



Animal oblong ; tentacles clavate, retractile within sheaths ; 

 mantle margined with filaments ; gills few, pinnate, around or 

 in front of the dorsal vent. (A. and H.) Lingual teeth 8.1.8, 

 or 8.0.8. 



Distribution, 3 species. Norway and Britain, Low water — 

 20 fathoms. 



^GiEUS, Loven. 



Type, JE, punctilucens, PI. XIIL, Fig. 4 



Etymology, ? aix {aigos), a goat. 



^m"ma/ oblong or elongated, covered with very large tubercles; 

 no distinct mantle ; tentacles linear, retractile within prominent 

 lobed sheaths ; gills dendritic, placed around the dorsal vent. 

 (A. and H.) Lingual teeth 17.0.17. 



Distribution, 3 species. Norway, Britain (2 species), France. 

 Littoral zone. 



Thecacera, Fleming. 



Etymology, theJce, a sheath, ceras, a horn. 



Type, T. pennigerum, Mont. 



Animal oblong, smooth ; tentacles clavate, laminated, re- 

 tractile within sheaths ; head with a simple frontal .veil ; gills 

 pinnate, placed round 'the dorsal vent, and surrounded by a row 

 of tubercles. (A. and H.) 



Distribution, Britain, 2 species. Length, |- — ^ inch. Found 

 at low water. 



PoLYCERA, Cuvier. 



Etymology, polycera, many horns. 

 Type, P. quadrilineata, PI. XIIL, Fig. 5. 

 Animal oblong or elongated ; tentacles laminated, non- 

 retractile, sheathless ; head-veil bordered with tubercles or 



