Fam. 3, Plate 4. 



Genus 12. DOTO,* Oken. 



Corpus limaciforme, elongatum : pallio nullo : Caput terminate, velo parvo obtectum. Tentacula 

 duo, dorsalia, linearia, intra vaginas patentes retractilia. Branchia clavatse vel ovatae, tubercnlis 

 verticillatis muricatse, tinea unica utrinque dorsi dispositse. Pes linearis. Orificia generationis et ani 

 ad latus dextrum. 



The genus Doto was established by Oken in his ' Lehrbuch der Naturgeschichte,' pub- 

 lished at Jena in 1815, f for the Doris pinnatijida and D. maculata of Montagu. This genus 

 has been overlooked by most of the subsequent writers on the Nudibranchiata, who have 

 erroneously placed the species belonging to it in other genera — Tritonia, Tergipes, &c. More 

 recently they have been referred to Melibcea. M. Sander Rang formed the latter genus for 

 a mollusk obtained by him on floating sea-weed near the Cape of Good Hope, and first 

 published it, we believe, in his c Manuel des Mollusques,' in 1829. It approaches very near 

 to Doto, but differs in having a large funnel-shaped veil fringed inside like that of Thethys, 

 and a proboscidiform mouth. These differences, we think, are sufficient to warrant our 

 considering the two genera distinct : but however that may be, the name of Doto has an 

 undoubted priority, and must be adopted for our British species. 



This genus has generally been considered to be allied to Tritonia. An examination of 

 its internal structure, however, proves its greater affinity to Eolis, not only in its branched 

 digestive system, but also in the liver being entirely placed in the branchial processes ; in 

 which respect it shows much more decidedly the typical characters of the family than 

 Dendronotus, though allied to that genus in external form, and consequently placed in the 

 same sub-family. It is also related to Dendronotus by the position of the ovarium, which is 

 above the central vessel or hepatic duct. By this circumstance, as well as in the largely 

 developed salivary gland, it shows an alliance to the Dorididce, and forms another link in the 

 chain of affinities that unites the order. 



The body of Doto is limaciform and elongated, rounded on the back, and without any 

 cloak or carinated ridge. The head is covered by a short veil, plain at the edges. The 

 mouth is small, round, and puckered. There are two tentacles which are slender and linear, 

 retractile within sheaths, usually expanded and curved outwards at the top : they are 

 situated dorsally nearly above the mouth. 



The branchial processes are arranged in a single row along each side of the back. 

 They are of an ovate or clavate form, slightly pedunculated, and covered with transverse 

 rows of bluntly-pointed tubercles, capable of extension and contraction. These processes 



* Doto, a sea-nymph. 



t The name has since been used by De Haan for a genus of Crustacea, published in 1836 ; and 

 we believe also, by Gnerin, for another genus of Crustacea, during the same year. 



