1888.] NATURAL SCIENCES OF PHILADELPHIA. 327 



SO imperfectly characterized that it is almost impossible to determine 



its exact relationships. 



Chiomodoris zebra, n. sp. (PI. 16, figs. 3, .3a.) 



Animal of the form typical of the gemis ; head portion consider- 

 ably extended and expanded in motion ; caudal portion moderately 

 elongated ; base flattened ; mantle beaded immediately over the tail. 



Color bright blue above, variously lined and streaked with light 

 yellow ; on the dorsal surface the yellow markings are disposed in 

 longitudinal wavy or nearly straight lines, one or more specially 

 prominent lines along the dorso-lateral border. Sides of animal ir- 

 regularly reticulated or angulated with yellow markings ; under 

 surface pale blue, bordered with faint yellow. 



Rhiuophores deep indigo or black, the rhinophoral aperture border- 

 ed with yellow ; gills 12 or 13, black, bordered with yellow, and carry- 

 ing blue cilia ; under surface of head blue, Avith yellow spots. 



Length, when expanded, three and a-half inches. 



Three specimens, dredged in about ten fathoms on the north side 

 of Harrington Sound. I dissected one of these and found that the 

 stomach is lodged entirely within the mass of the liver. The ali- 

 mentary canal is sharply deflected forward (dorsally) beyond the 

 buccal or oesophageal tracts, and is caught up in a nerve ring pro- 

 ceeding from the supra-oesophageal ganglia. 



This species appears to be third or fourth of the genus found in 

 the western Atlantic. It differs clearly from the C. picturata of 

 Morch ( C. Morchii, Bergh, 3Ius. Godef., part xiv) and C. gonafophora 

 of Bergh, two West Indian species. In the scheme of coloring the 

 species appears to be nearest to Doris pulcherrwia of Cantraine {Mal- 

 acologie Mediterraneenne, p. 57, PI. 3, fig. 6, = D. Villafranca f of 

 Risso), from which, however, it differs in a number of details, such 

 as the number of gills, etc. 

 Onchidium (Onchidiella) trans-Atlanticum, n. sp. (PI. 16, figs. 4, 4a.) 



Body convex, smoke color or dark olive ; lighter, dirty or greyish 

 green on the under surface ; pedal disk considerably more than one- 

 third the width of base, yellowish green ; mouth margin papillose, 

 bunchy ; under surface obscurely or obsoletely tuberculose ; dorsal 

 surface closely verrucose, with finer granules interspersed between 

 the warts. 



Anal aperture immediately beyond the extremity of foot, infra- 

 marginal to a raised border; respiratory orifice between the anal 

 pore and the apex of l)ody. 



