ON THE 



RELATIONS OF HESSE'S DOTO UNCINATA 



TO THE GENUS HANCOCKIA. 



By WALTER GARSTANG, M.A., F.Z.S., 

 Marine Biological Association, Plymouth. 



Having recently had occasion to refer to M. Hesse's " Memoire sur 

 douze Mollusques Nudibranches nouveaux, recueillis en rade de 

 Brest,"* I have been surprised to find, hidden under the unsuspicious 

 heading Doto uncinata, the description, accompanied by three 

 coloured figures, of an animal belonging to a much rarer and still 

 more interesting genus than that to which M. Hesse has assigned it. 

 The species, in fact, belongs very clearly to the genus Hancockia of 

 (lossef ( = Govta, Trinchese. | | 



M. II esse gives the following as the chief characteristics of his 

 species : — Body elongated, of an intense carmine-red ; frontal veil 

 thin, provided on each side with an anterior trilobed appendage, 

 bordered with green ; rhinophores simple, of a clear green colour, 

 arising from a conical sheath (wider above than below), with 

 a rounded and entire margin, and of a carmine-red, bordered with 

 green ; " branchial lobes," four on each side, of relatively small size, 

 each having an incised appearance and being composed of four 

 hooked tubercles set over against one another, and together bringing 

 about a resemblance to a developing fern leaf (" comme cela se voit 

 dans la prefoliation des frugeres ") ; colour of lobes carmine-red with 

 a border of clear green ; foot sharply truncated posteriorly ; total 

 length 5 mm. 



M. Hesse draws attention to the exceptional peculiarities of his 

 interesting capture ; and his description and figures, moreover, are 

 so clear and good that it is most remarkable to find that Prof. Bergh 

 in his recent revision§ has disposed of Doto uncinata as a mere 

 synonym of the common Doto corona/a. The structure of the veil 

 and especially of the pleuropodial ("branchial") lobes, together with 



•Journ. de Conch., (3) xiii., 1873, pp. 305-314, Plates xii., xiii. 



fAnn. Mag. Nat. Hist., (4)xx., 1S77, pp. 316-319, Plate xi. 



► Mem. R. Ace. Sci. Inst. Bologna, (5) vii., 1S86, pp. 183-191, one plate. 



gSystem der Nudibranchiaten Gasteropoden. Semper's Reisen im Archipel der Philippinen 

 <2)ii., xviii., 1892, p. 1046. 



