APLYSIID®. 63 
Pl. 62, figs. 1, 2, represent Ac/esia pleit ; fig. 3, isa diagrammatic 
figure representing the internal structure of the annexed genital 
mass of Aplysia. 
Laterature of the Aplysiide. 
(1) After the early work of Bonapsca on the anatomy, and 
LinnE on the “system,” of Aplysia, the group received little atten- 
tion until (II) Cuvier published his Memoire sur le genre Aplysia 
in 1805. This was followed by an anatomical and systematic mon- 
ograph of the Mediterranean forms by DrELLEe Carase (1823), and 
an illustrated monograph by BLarinvILLy in Journal de Physique, 
etc., Vol. 96,1825. This monograph is the only systematic work 
on the group which the writer has not seen. Its substance seems to 
be repeated by Blainville in his articles, “ Litvre marin” and 
“ Dolabelle,’ in the Dictionnaire des Sciences Naturelles, 1819, 
1823. See also his Manuel de Malacologie, 1825. 
The next stage (III) in the history of the group is represented 
by Rana’s monographic Histoire Naturelle des Aplysiens, 1825; one 
of the most satisfactory monographs ever written on a mollusk 
group, and, although now nearly seventy years old, still singularly 
useful and complete. Scarcely any descriptions of species by more 
recent writers approach those of Rang in lucidity and comprehen- 
siveness. All of the main genera were understood by Rang, 
although he considered them subdivisions only of Aplysia, using 
that generic term in a rather wider than Lamarckian sense. Sub- 
sequent systematic work on the family has added little to Rang’s 
foundation aside from new species. The genera Aplysia, Dolabella 
and Dolabrifera have been monographed by SowERBy in the Conch- 
ologia Iconica, but as the plan of that work excluded all but purely 
shell features, these treatises are practically useless in the study of 
the Aplysiide, the shells of which are comparatively uncharacter- 
istic. 
- (IV) In quite recent times the Ap/ysiide have attracted the at- 
tention of numerous morphologico-systematic zoologists, among 
whom may be mentioned BLrocuMANN, Mittheil. Zool. Sta. Neapel, 
1884; VaysstERE, Recherches sur les Mollusques Opistobranches, 
1885, MazzareE_i, Atti della R. Accademia Scienze, etc., Napoli, 
1890, 1891; Zool. Anz., 1889, etc.; Zuccarpi, Boll. Soc. Nat. 
Napoli, 1890, and others. Nearly all of these investigations have 
been made on Mediterranean forms. 
