EUNICEA LABIDOGNATHA NUDA. 369 



deeply stained nerve-cells not only form an external investment, but go downward 

 almost to the outer end of the pedicle. 



In the mid-dorsal line a mobile band passes from the circular layer to the muscular 

 walls of the dorsal blood-vessel, and thereafter is continued to the arch of the alimentary 

 canal, the nuclei of the cells of which are mostly external. 



The form mentioned by Donati 1 as living in a cavity or tunnel in a sponge is probably 

 one of this family (Lumbriconereidae), from its general structure and iridescence. The 

 figures are, however, too indefinite for accurate identification. 



Pallas described an example under the title Nereis ebranchiata, and De Blainville 

 placed the Lumbricus fragilis of 0. F. Miiller under the genus Scoletoma. 



Grube, 2 after Savigny, made Lumbriconereis one of "the genera of the Euniceae, the 

 others being Diopatra, Onuphis, Eunice, Lysidice, Aglaura, and (Enone. 



The Lumbriconereicla constitute the fifth family of Kinberg's 3 Eunicea, characterized 

 by eight maxilla), part Ii edentate, tentacles tubercle-like or none, branchiae absent. He 

 gives only two families, viz., Eranno, in which the tentacles are two and tuberculiform, 

 and Lumbriconereis, in which they are either obsolete or absent. 



Claparede and Mecznikow (1868) 4 give an account of the development of what they 

 considered a Lumbriconereis or an allied form. The youngest stage is spherical, with a 

 long tuft of cilia in front, two reddish eyes with lenses, a general covering of cilia, with 

 a gap posteriorly, and then a broad but short caudal tuft. The alimentary canal and its 

 glandular coat are differentiated. The following day the outline is pear-shaped, and the 

 posterior ring of cilia is better developed. On the fourth day greater elongation ensues, 

 and the proboscis is apparent, whilst the broad anterior coating of cilia and the caudal 

 ring are more conspicuous. Then a few larval bristles appear on each side posteriorly, 

 and this region soon shows two distinct tufts of bristles elevated on rudimentary feet, and 

 a pair of short caudal cirri on cirrophores, whilst the proboscis is armed with what appear 

 to be maxillae, great dental plates, and mandibles in an early condition. 



Cams (1885) makes the Lumbriconereidae a sub-family of the Euniciclae. 



Hacker (1896) quotes Fewkes as stating that Lumbriconereis lays eggs in galleries, 

 and has non-pelagic young. Fewkes says that from each pigment-spot, cephalic or 

 caudal, a number of delicate threads pass toward the centre of the larva, and that they 

 are ultimately lost in the larval body. 



In his 'Annelids of the Shores of Dinard,' De St. Joseph, 5 while criticising Grube's 

 classification, which he considers to be a combination of the systems of Kinberg and 

 Ehlers, follows a similar arrangement. 



The veteran student of the Annelids, Prof. Grube, G published, the last year of his life 

 (1879), a careful general account of the Lumbriconereiclea, primarily subdividing them 

 according to the absence or presence of dorsal cirri, the bristles and teeth being of 



1 ' Delia Storia Naturale Marina dellAdriatico/ Venezia, 1750, p. 59, Tav. viii, figs. G, h, j, k. 



2 f Fam. der Annel./ p. 293, 1851. 



3 < Ofvers. af-K. Vet.-Aead./ 1864, No. 10, p. 567. 



4 'Zeitschr. f. wiss. Zool./ xix, p. 182, Taf. xv, figs. 1 — In. 



5 < Ann. Sc. nat./ 7 e ser., t. v, p. 192, 1888. 



e < Jahresber. Scliles. Gesellsch./ 1879, p. 78. 



10-1 



