no.1761. I VEW SPECIES OF OXCHIDIOPSIS BALCH. 177 



ine, after some discussion based on considerable material (all from 

 one locality, however), thai graznlandica is al most a variety of gla- 

 dalis. He did not have pacified before him. He found that four 

 out of the eight specimens which he separated as gramlandica from his 

 single specimen of glacialis had black osphradia, but one of them had 

 also denticulate uncini. 



The present species is evidently fully congeneric, but is much 

 farther from any of the above forms than any of them are from one 

 another. It is impossible to say to which if comes nearest. Like 

 gra nlandica, it lias an osphradium with black base and nondenticulate 

 inner uncinal hooks in the radula. In the median tooth ("rhacliis" 

 of Bergh), and in the character of the notaeum, it is nearer glacialis. 

 In the very peculiar penis it is perhaps nearest pacifica. But in the 

 smooth notaeum with reticulate pattern, the extraordinary penis, the 

 shape of the jaws, the shape of the osphradium leaflets, and above all 

 in the structure of the shell, it is sharply distinguished from any of 

 them; while there are minor points of individuality in the radula, 

 the shape and musculature of the rostrum, the form of the tentacles 

 and proportion of the eyes, the form of the body and notaeum (espe- 

 cially the anterior lappets), and the shape of the gill leaflets. 



It would seem that the species of the genus should for the present 

 be written as follows: 



0. glacialis (Sars, 1850), colorless osphradium, slightly denticulate uncinal hooks, 

 comparatively smooth notaeum, gill leaflets not auriculate at tip. Distribution paleo- 

 boreal and arctic. 



0. glacialis, v&r.grcenlandica Bergh, L853(syn.: carina, recondita,reinhardti,palliata), 

 osphradium with black base, nondenticulate uncinal hooks (occasionally denticulate), 

 warty notaeum, gill leaflets auriculate at tip. Distribution paleo-boreal and arctic. 



0. glacialis, var. pacifica Bergh, L887, osphradium as in last, uncinal hooks usually 

 strongly denticulate (sometimes smooth), rhacliis peculiar, penis peculiar, notaeum 

 as in last. Distribution pacifico-boreal. 



O.corys, new species, osphradium with black base but peculiar form, uncinal hooks 

 smooth (in the unique specimen), notaeum (top) smooth, gill leaflets not auriculate, 

 penis peculiar. Distribution neo-boreal (".'). (Further distinguished from the glacialis 

 forms by shell, etc., as elsewhere stated.) 



THE RELATIONSHIPS OF ONCHIDIOPSIS TO OTHER GENERA OF 



LAMELLARIIDjE.o 



The Lamellariidae constitute a small, highly aberrant, and some- 

 what heterogeneous family, treated by Bergh as distinct from the 

 Velutinidse and containing only the genera Ghelynotus b (Swainson) 

 Bergh, Marsenia Leach [ = Lamellaria Montagu], Marseniella Bergh, 

 Marseniopsis Bergh, Mawsenina Gray, and Onchidiopsis (Beck) 

 Bergh. The Velutinidae, however, are included in the same group 



a Called by Bergh and some others Marseniadae, but luckily the more familiar na 



La mi I hi r la fur i he typical genus appears to he correct under the International Ru] 

 rather than Mar.srnia. 



& Better treated as a subgenus of Lamellaria. 



