4 LEODICID^E OF THE WEST INDIAN REGION. 



Preservation in formalin gives very poor results with annelids, and the strong 

 alcohol is more satisfactory than the lower grades. My collecting was done along 

 shore or in comparatively shallow water, so that I did not see some of the deeper- 

 water forms described by Ehlers. 



In the drawings the scale of magnification is given after the legend. It should 

 be remembered that in annelids the size of individual organs varies with the degree 

 of expansion of the animal, and there is often variability in the size of adult animals 

 of the same species. All text-figures except 53 and 287 were drawn with the camera 

 lucida. In the preparation of the colored illustrations I had the assistance of Messrs. 

 K. Morita, S. C. Ball, S. C. Rowland, R, Weber, Duncan Gay, and Miss Helen 



Fernald. 



CLASSIFICATION. 



Originally classified as Nereis, the principal genus of this family was first 

 recognized as distinct by Cuvier (1817, pp. 524 and 525), who named it Eunice 

 and subdivided "Les Nereides" into "Les Nereides proprements dits" and "Les 

 Euniciens." These were soon separated from Nereis under the family name 

 Eunicidw, by which they have since been known. Verrill, however (1900, p. 638), 

 showed that the name Eunice was in use in 1816 for a genus of insects, and the law of 

 priority requires us to abandon it for the annelids. This leaves the name Leodice 

 given by Savigny (1820, p. 13) as the true name of the genus and correspondingly 

 of the family. 



The Leodicidce are a well-defined family in which the most constant structures 

 are internal rather than external. To the practised eye the general appearance of 

 the animals is quite characteristic, though in the presence or absence of append- 

 ages there may be a very great amount of variation. There is always a well- 

 developed jaw apparatus, composed of bilaterally arranged series of chitinous plates 

 developed in a pharyngeal pouch, and capable of protrusion for feeding 

 purposes through the mouth. The structure of these jaws was used by Ehlers as a 

 basis for classification, though the external organs are a more convenient means 

 of recognition. 



In the present paper I have employed for identification certain characters 

 which I have found reasonably constant, though all subject to more or less indi- 

 vidual variation. All of the external characters except the form of the setae are 

 liable to distortion through the action of the preserving fluids, which increases the 

 difficulties in the way of basing accurate descriptions on preserved material. I 

 believe that the preserving methods I have used reduce this difficulty to a minimum, 

 and in all but a few species the living animal has been studied. An explanation 

 of the characters employed will render the later descriptions more intelligible. 



1 . Size and color: While size variations do occur, and in the poorly preserved 

 material frequently sent to the systematist for study are often much exaggerated 

 by the action of the preserving fluids, I did not find the range of variation extreme 

 in the living, mature animals. Differences of size are perhaps more variable than 

 other characters, but are of diagnostic importance. In most species the color of 

 the living animal is characteristic, though obviously this depends on whether the 



