GASTEHOrOUA. 321 



(Goodsir.) In old times they were objects of superstitious 

 dread, on account of their grotesque forms, and the imaginary 

 properties of their fluid, which was held to be poisonous and to 

 produce indelible stains.* 



Fossil, one or two shells of the newest tertiary in Sicily have 

 been doubtfully referred to this genus. 



Suh-genus. Aclesia (dolabrifera), Eang. Shell trapeziform. 

 Side -lobes closely enveloping the body, leaving only a small 

 dorsal respiratory opening, sui'face ornament with filaments. 

 9 species. East Indies. 



DoLABELLA, Lamarck. 



Type, D. Eumphii, PI. XIV., Fig. 15. 



Etymology, dolabella, a small hatchet. 



Shell hard, calcareous, trigonal, with a curved and callous 

 apex. 



Animal like Aplysia, with gill near posterior extremity of the 

 bodj'" and lateral crests closely appressed, leaving only a narrow 

 opening ; ornamented with branching filaments. 



Distribution, 12 species. Mediterranean, Mauritius, Ceylon, 

 Society Islands, Sandwich Islands. 



Stylocheiltjs^ Gould, 1841. 



Synonym, Aplysia longicauda Q. and G. 



Animal \imQ.Q,iiovTQ., cirrigerous, dilated at the sides, attenuated 

 behind; neck distinct; tentacles 4, long, linear, papillose, far 

 apart ; lips dilated laterally into tentacular processes. 



Distribution, 3 species. New Guinea, on Fuci. 



Dolabrifera, Grube. 



Shell trapezoidal ; side-lobes not used for swimming. 

 Distribution, 4 species. Indian Ocean, West America. 



SiPHONOfYGE, Brown. 



Shell truncated in front ; foot-lobes spread out for swimming; 

 posterior part extended beyond the siphon. 



Distribution, 6 species. West America, Chinese Sea. 



NoTARCHUS, Cuvier. 



Type, N, Cuvieri, Bl. 



Etymology, notos, the back, archos, vent. 



Synonym, Busiris (griseus), Risso, ? Bursatella (Leachii), Bl. 



* Aplysia (from a and pluo) ua-washable : the Aplysia of Uie Greek fishennen 

 were sponges unfit for washing. 



