12 ENTOZOA. 



special twigs being transmitted to the pits or depressions occurring 

 on either side of tlie head which, moreover, have been described 

 as "respiratory fossas." The habits of the Nemertidse have been 

 amusingly descanted on by Dalyell, Montague, Rymer Jones, 

 Gosse, and others, but we now stand in need of a careful reinvesti- 

 gation of the anatomical peculiarities, development, and relations 

 of the entire group. 



Genera. — Nemertes, Cuvier ; Polia, Delle-Ohiaje ; = Baseodis- 

 ciis, Diesing ; = Borlasia, Oken ; = Tceniosoma, Stimpson ; = 

 Valencinia, Quatrefages ; = Qiiatrefagea, Diesing ; Polyhoj^la, Die- 

 sing ; Meckelicty Leuckart ; = JSfotospermus, Huschke ; Notogymnus, 

 Hemprich and Ehrenberg ; Ojohiocephalus, Quoy and Gaimard ; 

 Golpocephalus, Diesing; Ghlamydocephalus, Diesing; Astemma, 

 Oersted ; Polystemma, Ehrenberg ; HemicycUa, Hemprich and 

 Ehrenberg ; Ommatojplea, Ehrenberg ; Amphiporus, Ehrenberg 

 Cephalothrix, Oersted; Emea, Leidy; Tetrastemma, Ehrenberg 

 ? Hecate, Girard; Serpentaria, Goodsir; Garinella, Johnston 

 LinnetLS, Sowerby; ?Lineus, Beattie and Gray; Gerebratulus, Renier 

 Micrura (and larval Pilidmm), Ehrenberg; Acrostoma, Grube 

 Biplomma, Stimpson ; Nareda, Girard ; Oerstedia, Quatrefages 

 Tatsnoskia, Stimpson; Polina, Stimpson; Gosmocephala, Stimpson 

 Bamphogordius, Rathke ; Stimpsonia, Girard ; Lohilahrum, Blain- 

 ville ; Prorynchus, Schultze ; Tubulanus, Renier ; ? Beneria, Girard ; 

 ? Siphonenteron, Renier ; Leodes, Girard ; Biplopleura, Stimpson ; 

 Gephalonema, Stimpson ; DitactorrhocJima, Diesing ; Loxarrhochma, 

 Schmarda ; Empledonema, Stimpson ; ? Dichilus, Stimpson ; 

 ? Lumbricaria, Miinster ; ? Nemertites, Murchison ; ? Gololites, 

 Agassiz ; ? Medibsites, Germar. 



In the briefest possible manner I have thus designedly sketched 

 the typical and leading family characteristics of the Turbellaria, 

 simply for the purpose of communicating a clear conception of the 

 true position and affinities of this singular and comparatively little 

 known class of worms. As before hinted, much remains to be 

 accomplished in the way of our rightly understanding the visceral 



