1877.| ANTHOBRANCHIATE NUDIBRANCHIATE MOLLUSCA. 197 
as ‘the worm itself,” while the upper lamella, which is really the 
principal part of the body of the animal, is regarded as a kind of 
protecting house. The number of species of Doris was increased to 
12 by O. F. Miiller in 1776; and subsequently most of them were 
figured in his ‘ Zoologica Danica, Six of the new species, however, 
do not correspond with Linneeus’s' genus, and in fact, belong to other 
sections of the Nudibranchiata. Gmelin followed Miller, and still 
further enlarged the genus to include 25 species. The genus Doris, 
thus made to be almost synonymous with what we now understand 
as the ** Nudibranchiata,’” was reduced by Cuvier in the ‘Tableau 
élémentaire d’ Histoire Naturelle,’ 1798, to its original Linnzean signi- 
fication, and shown to include but 7 of the previously enumerated 
species. In the ‘Annales du Muséum’ for 1804, Cuvier wrote a 
classical article on Doris, in which he brought forward 13 species, 
giving more or less lengthened descriptions of several of them, and 
figures of six. He divided the genus into ‘ Les Doris planes,’ and 
‘Les Doris prismatiques.’ In 1814, in his memoir on a new classifi- 
cation of Mollusca, De Blainville proposed the name ‘ Cyclobranches’ 
(Cyclobranchiata) for his 4th order of “ Cephalic } Mollusea,” to in- 
clude those “ which have the organs of respiration symmetrical, 
hidden or exposed, and placed in a circle on the posterior portion of 
the body.” Cuvier, in 1817, ignored this, and used the same term 
for the 7th order of the class Gasteropoda, to embrace the Chitons and 
Patellas. He has been so very generally followed that it would only 
create confusion now to employ the name in its original meaning. 
In the same year Cuvier called the whole of the naked-gilled Mol- 
lusks ‘‘ Nudibranches”’ (Nudibranchiata) ; and in 1820 Goldfuss, 
shortly followed by Férussac, named those with the branchiz 
surrounding or near the anus on the medio-dorsal line, ‘“ Antho- 
branches” or ‘‘Anthobranchiata,”’ the nomenclature now adopted. 
From the commencement of this century, the number of known 
species has been largely increased by scientific voyagers and by home 
workers. 1n 1817 Risso described 6 Mediterranean species in the 
‘Journal de Physique,’ a number that he increased to 10 in his 
‘ Histoire Naturelle de Europe Méridionale’ of 1826. In a mono- 
graph, ‘ Ueber das Molluskengeschlecht Doris,” published in the 
‘Nova Acta Nat. Cur.’ in the latter year, Rapp enumerated 27 forms, 
among which 6 were new; several of them he figured. Riippell 
and Leuckart, two years afterwards, described and figured 12 new 
species in the ‘ Atlas zu der Reise im nérdlichen Afrika.” Ehrenberg, 
in 1831, described 15 new varieties in his ‘Symbolee Physicee ;’ and 
this naturalist enunciated a somewhat elaborate classification, founded 
upon differences in the arrangement of the branchial apparatus of 
the animals before him. His system has not been found to hold 
ood. Inthe following year, Quoy and Gaimard, in the ‘ Voyage 
de l’Astrolabe,’ gave drawings and descriptions of 21 species of 
Doridide, all but three of which were new. ‘They were chiefly from 
the Malayan, Australian, and Pacific Islands. Other naturalists who 
have principally increased our knowledge of these Mollusks have 
been :—D’Orbigny, to whom we owe 12 or 13; Cantraine, who enu- 
