( 77 ) 



VIII. — On the Structure of Lerneopoda Dalmanni, with Observations on its Larval 

 Form. By William Turner, M.B. (Lond.) F.R.S.E., and H. S. Wilson, M.D., 

 Demonstrators of Anatomy. (Plate IV.) 



(Read 7th April 1862.) 



The first example of this, apparently little known, species of Parasitic Crusta- 

 cean appears to have been noted by Professor Otto.* The celebrated Swedish 

 naturalist Retzius was, however, the first to give, in 1829, an anatomical descrip- 

 tion of it.f He named it Lemma Dalmanni. His description was accompanied 

 by several figures, which, though in many respects imperfect, enable one to 

 recognise the chief external characters of the animal. He found three specimens 

 at Christian Sound, in the nasal cavity of Raia Batis. Von Nordmann X obtained 

 from RuDOLPHi the specimen discovered by Otto, but it was so injured, that he 

 adopted, in his account of the anatomy of the animal, the description of Retzius. 

 Some years afterwards, in 1836, Kroyer || added it to the Danish fauna. He 

 states that he obtained two specimens from the nasal chamber of a skate brought 

 to him by a fisherman from Aal-back, and that specimens from Iceland had been 

 for several years in the possession of the Natural History Society. As naturalists 

 had now begun to subdivide the old Linnean genus Lernsea into various genera, 

 Kroyer added this animal to the genus Lerneopoda of De Blainville, and, con- 

 tinuing its specific name, termed it Lerneopoda Dalmanni. 



Since the time of Kroyer but little attention appears to have been bestowed 

 on this parasite by systematic writers. Milne Edwards § mentions it only briefly, 

 and is inclined, from the elongated and cylindrical form of the cephalic part, and 

 from the development of two processes from the ventral aspect of the posterior 

 end of the body, to place it in the genus Brachiella. 



It does not appear to have been, as yet, recognised as a British species, for no 

 mention of it is made in the systematic works of Baird and Gosse. The for- 

 tunate detection by one of us (Dr Wilson) of several specimens, early in the pre- 

 sent year, in the nasal cavities of more than one skate, caught by the Newhaven 

 fishermen, has enabled us to add it to the British fauna, and to investigate its 

 anatomy. 



* Mikrographische Beitrage Von A. v. Nordmann. Berlin, 1832. 



f Kongl. Vetenskaps Acad., Handlingar. Stockholm, 1829. P. 109. Frorieps Notizen, 

 vol. xxix. N. 617, p- 6. 

 + Op. Cit. p. 139. 



I] Naturhistorik Tidskrift, vol. i. p. 264. Okens Isis, 1840, p. 746. 

 § Hist. Nat. des Crustacees, vol. iii. p. 516. 

 VOL. XXIII. PART I. Y 



