ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
577 
forms being more remote. The scheme of relationship which Bergh 
supports is as follows : — 
The memoir gives diagnoses of the various families of cladohepatic 
Nudibranchs noted in the above scheme from the iEolidiidae which are 
nearest to the Ascoglossa, to the Tritoniidae, which approach most 
closely to the.holohepatic forms. 
The Titiscanise.* — Dr. R. Bergh establishes the new genus Titi- 
scania, and makes it the type of a family of Rhipidoglossal Proso- 
branchiates. The animals are shell-less and slug-like ; in internal 
structure, e. g. gills and lingual armature, they belong distinctly to 
the group Neritaceae ; while the structure of the radula and the absence 
of the median plates suggest a position in the subdivision Neritopsidae. 
Bergh gives a detailed account of Titiscania limacina sp. n. from one 
Tritoniidae 
Pliylliroidae 
Dendronotidae, Bornellae, Scyllaeae 
Dotonidae, Lomanotidae 
Pulmonata 
(Pulmonata stylommatophora) 
(Janidae) 
iEolidiidae 
Brancliiopneusta 
(Pulmonata basommatophora) 
(Phyllobrancliiidae ) 
Ascoglossa 
Stegauobranchia 
(Tectibranchia) 
* Morphol. Jahrb., xvi. (1890) pp. 1-26 (8 pis.). 
