Fam. 3. 



{The Figures are included in PL 5 of Fam. 2.) 



Genus 10. EUMENIS,* Alder and Hancock. 



Corpus elongatum, quadrilaterurn. Caput sub-inferius, velo parvo obtectum; maxillis corneis. 

 Tentacula duo, dorsalia, clavata, et laminata, intra vaginas retractilia. Branchiae sub-papillosse, mem- 

 brano undulato, ad latera dorsi utrinque longitudinaliter extenso. Pes linearis, Orificia generationis 

 et ani ad latus dextrum. 



This genus was formed by us for the reception of a curious animal found in Torbay ; and 

 was published in the ' Annals of Natural History' for November, 1845. Since then we have 

 met with another species in Lamlash Bay, Isle of Arran, agreeing in all essential particulars 

 with the characters on which we had founded the genus, and consequently strengthening our 

 opinion that those characters are generic. In external form this genus very much resembles 

 Tritonia, but it differs from it in the papillose character of the branchiae ; in which respect, 

 as well as in its internal structure, it shows a much nearer alliance to the Eolidida, amongst 

 which we have placed it. It constitutes, however, an intermediate form uniting the two 

 families. 



The body of Eumenis is elongated and quadrilateral, truncated in front, and ending in 

 an obtuse point behind. The head is sub-inferior, with corneous jaws, and is covered by a 

 small tuberculated veil ; there are two tentacles, which are dorsal, clavated, and laminated, 

 and are retractile within small, plain, or tuberculated sheaths. The branchiae are sub-papillose, 

 and arise from a waved membrane set along each side of the back, forming a continuous base 

 from which the papillae arise into obtuse points. The sides of the body are vertical. The 

 foot is linear, but not very narrow, deeply cleft and arched in front, and extending into long 

 tentacular processes at the sides. The orifice of the generative organs, and the anus are on 

 the right side. 



In consequence of our observations having been confined to a single individual in an 

 imperfect state of preservation, the anatomy of this genus has not been very fully made o ut. 



The buccal mass resembles very much that of Eolis, but is larger in proportion to the 

 size of the animal, and the muscles, though arranged in the same manner, are more pow erful. 

 The corneous jaws differ only in being flatter and shorter. The tongue is placed in the centre 

 of the mouth on a wedge-shaped muscle, and is composed of about fifteen transverse rows of 

 stout, well arched teeth or spines, minutely denticulated on each side, and having their p oints 



* Eumenis, a fury. Since the institution of this genus, we have found, in the volume of 'Reports 

 on Zoology,' lately published by the Ray Society, the description of a genus of M. Verany under the 

 name of Lomanotus, which appears to be similar to, if not identical with ours. We regret that our 

 not having had the opportunity of seeing the periodical in which this genus was published, prevented 

 our adopting it. Should it prove the same as ours, we believe M. Verany's name will have the 

 precedence. 



