TOMOPTERIS IDIURA. 161 



other parapodia, but rosettes occur in the bases of the fin-membranes in many 

 of the parapodia, though the exact distribution could not be determined satis- 

 factorily. (Plate 27, fig. 1). 



Length without tail, near 11.75 mm. Length of tail 7 mm., making the 

 total length 18.75 mm. 



Locality. Off Peru: Sta. 4659 (lat. 8° 51' S., long. 86° 05' W.). Surface 

 to 300 fms. 14 November, 1904. One specimen. 



This species is most readily distinguished from others by the presence of 

 a rosette in the trunk of the first parapodia and its absence from all others 

 excepting in the fins, together with the strikingly pecuUar long, slender, and 

 naked tail. The form of the brain and the form and structure of the parapodial 

 fins are also of diagnostic value. 



TOMOPTERIS IDIURA, Sp. nOV.^ 



Plate 27, fig. 4r-6. 



The body and appendages colorless, or nearly so, and transparent. 



There is a long, attenuated caudal division, or tail, upon which the para- 

 podia, while presenting the usual parts and general structure, are very much 

 reduced in size. The attenuation caudad takes place gradually, as does the 

 reduction of the parapodia to the minimum size. What may be regarded as 

 the body proper bears sixteen pairs of parapodia, while the tail, which is appar- 

 ently broken off at the tip, bears at present six pairs. 



Tentacles flattened, distally attenuated, and curved in the usual way. 

 No first tentacular cirri present. Second tentacular ckri of the usual form, 

 not fully as long as the body; in the type as at present, with the tip of the tail 

 broken off, they reach to the next to the last pair of parapodia, the latter being 

 at the broken tip. On each side of the head adjacent to the narrow region 

 bearing the tentacles there is a conspicuously developed ciliated epaulette, which 

 continues as a narrow band on the dorsal surface above the brain. (Plate 27, 

 fig. 4). 



The brain transversely oblong in outline, with the anterior face slightly 

 convex. The eye-pigment appears to have been black. The number of lenses 

 not determined. 



Fins of parapodia large and distally subcircular in outline and extending 



' Mijs, peculiar, and ovpa, tail. 



