DORIS. 



a. Branchiis simpliciter ligulatis. Glossidoris. 



b. 'Branchiis ligulatis, apicibus furcatis, incisisve. Actinodoris. 



c. Branchiis simpliciter radiatis, radiis simpliciter pinnatis. Pterodoris. 



d. Branchiis radiatis, ramosis, compositis, fructiculosis. Dendrodoris. 



He also describes four new genera founded upon foreign species, some of them rare, and 

 still remaining unfigured. His sub-genera, it will be observed, are formed from the character 

 and mode of branching of the branchial plumes. We do not think that these will be found 

 to lead, in all cases, to natural groups : to divide the simply pinnate from those with doubly 

 pinnate or branched plumes, would occasionally separate species very closely allied ; for instance, 

 no two species are more closely allied than our Doris Johnstoni and Boris coccinea ; yet, accord- 

 ing to Ehrenb erg's views, the former would be a Dendrodoris and the latter a Pterodoris. 



In our provisional synopsis to the present work, published in 1845, we divided the 

 British species of Doris into three sections, characterised by the position of the branchiae, and 

 their retractibility into a cavity or otherwise. These divisions, which we still adhere to, are 

 given below. 



But the most extensive subdivision of the Dorides is that of Mr. J. E. Gray, in the fourth 

 volume of Mrs. Gray's 'Figures of Molluscous Animals/ published in 1850. In this, 

 Ehrenberg's sub-genera are adopted and raised to the rank of genera, with the exception of 

 Pterodoris, which is left out, and Dendrodoris is divided into two, Dendrodoris and Doris ; the 

 former being restricted to species with the anus behind the branchiae, a distinction which we 

 think will not hold good, as the species therein enumerated have the anus really in the centre 

 to which the plumes converge, though the circle is incomplete. Our second section, which 

 Mr. Gray adopts as a genus, he considers to be the Onchidoris of Blainville ; the character on 

 which that naturalist separates his genus from Doris is not, however, to be found in the 

 animals composing this section. Our third section Mr. Gray forms into a genus under the 

 name of Acanthodoris. He also adopts the genus Villiersia of D'Orbigny, which we have 

 ventured to discard for reasons mentioned in our account of Doris depressa. Some other 

 genera proposed by Mr. Gray, having reference to foreign species only, we shall not at 

 present stop to consider, more especially as the descriptions of authors are in general so 

 imperfect, that without some more accurate information concerning structural peculiarities 

 (independently of colour and markings, which are frequently the only characters given) it 

 would be impossible to come to any very satisfactory conclusions with regard to the great 

 mass of species now included in the genus. For this reason, we shall content ourselves 

 with giving the following groups as sections only, though there can be little doubt that they 

 will ultimately rank as genera. 



Section 1. Branchiae united at the base, and retractile within a cavity; body more or less 



depressed; with oral tentacles. Type, Doris tuberculata. 

 Section 2. Branchiae set separately in an open circle, non-retractile ; without oral tentacles, 

 their place being supplied by a veil. Type, Doris bilamellata. 

 * Body not much depressed, with moderately sized spicula ; spawn generally of few 

 coils, and cup-formed. Type, D. bilamellata. 

 ** Body very flat, with large spicula, symmetrically arranged; spawn narrow, of many 

 coils. Type, D. depressa. 

 Section 3. Branchiae united at the base, non-retractile ; body convex ; oral tentacles indistinct, 

 united into a veil. Type, Doris pilosa. 



