36 APLYSIID/E. 



Genus notarchus, Cuvier. 



Body oval. Head with the posterior tentacles simple 

 and conical. Gills protruding from the branchial cavity. 

 Foot linear, narrow. 



Shell none. 



Syn. Busiris, Risso. ? Placobranchus, Rang. 



Ex. N. gelatinosus, Rang, pi. 60, fig. 1. 



The species of this genus live in floating masses of sea- 

 weed, and those with dilated feet swim by vertical move- 

 ments of the lobes. 



Species of Notarchus. 



Cuvieri, Blainv. ocellatus, Rang. 



gelatinosus, Rang. punctatus, Phil. 



griseus, Risso. 



Genus BURSATELLA, Blainville. 



Body globular, covered with unguiform appendages. 

 Head with the posterior tentacles ramified. Gills ex- 

 ternal, long and plumose. 



Shell none. 



Syn. Notarchus, Strains,, not Cuvier. 



Ex. B. Leachii, Blainville, pi. 60, fig. 2. 



In this genus the body is almost spherical, the mantle 

 opening is small, and the lateral lobes of the foot are not 

 developed ; there is no shell, and the four cloven tentacles 

 are beset with filiform appendages ; the branchial plume, 

 moreover, is very long and exserted. Possibly this form 

 may be identical with that of Aclesia, but from being pre- 

 served in spirits may have assumed a globular shape. 



