Genus 14. EMBLETONIA, Alder and Hancock. 



Corpus elongatum, limaciforme, non palliatum. Caput terminate, lateribus utrinque in lobuni 

 planum extensis. Tentacula 2, linearia, sublateralia. Maxilla cornea*. Branchiae papillose ad latera 

 dorsi, ut plurimum in simplici serie, utrinque dispositse. Anus et orificium generationis ad latus 

 dextrum. 



We described this genus in the ' Annals of Natural History' for November, 1844, under 

 the name of PterocMks ; but having since ascertained that the name has been already used 

 for a genus of Hymenopterous insects, we now propose to substitute for it that of Embletonia, 

 in honour of our friend Dr. Dennis Embleton, from whom we have received such able 

 assistance in the anatomical part of this work. The genus is closely allied to the Eolides of 

 our fourth section ; but differs from them in having only two tentacles, the oral pair being 

 here supplied by an expansion of the sides of the head into flattened lobes. The dorsal 

 tentacles, too, are placed much more laterally than in Eolis, and at a greater distance from the 

 eyes. There is at present only one ascertained British species, unless the small nudibranch, 

 noticed under the name of Eolidia mimta by Professor E. Forbes at the Birmingham meeting 

 of the British Association in 1839,* should prove to be distinct from that here described. 

 Two American species of the genus have been discovered by Dr. Gould of Boston, which, as 

 far as we know, remain yet unpublished. The Tergipes aclspersus\ of Nordmann, which is 

 described as having the oral tentacles triangular, appears to be closely allied to Embletonia. 

 The species are all minute, and belong to the littoral and laminarian zones. There can be 

 little doubt that they are carnivorous. 



The body in this genus is elongated and nearly linear, tapering behind. The head is 

 terminal and furnished with two flattened lobes, broadly expanded laterally, and forming a 

 kind of veil. The mouth is inferior ; it has large corneous jaws, and a narrow denticulated 

 tongue. The tentacles are two in number, linear, generally short, and placed very much 

 apart towards the sides of the head. The eyes are situated considerably behind them. The 

 branchiae are papillose, as in Uolis, and are generally placed in single series down each side of 

 the back, alternating posteriorly. The great central hepatic vessel, partaking of the colour 

 of the branchiae, may usually be seen undulating down the back. In the American species 

 there is more than one row of papillae on each side. The foot is linear, truncated in front, 

 and without any lateral expansion. The anus is placed on the right side, a little behind 

 the generative organs, which are situated below and between the first and second papillae. 



Its anatomical characters, as far as they have been ascertained, are as follow :— The 

 oral opening is beneath in the form of a longitudinal slit between two narrow lateral lips. 

 The buccal organ is provided with a pair of large corneous jaws (PI. 38, fig. 5) of a 



* See f Athenaeum' for August 31, 1839. 

 t Ann. des Scien. Nat., 3d ser. v, p. 110. 



