LEOCEATES ATLANTICA. 133 



LXXVIII, figs. 5 and 5a) form a dense tuft. The shaft has a close series of 

 longitudinal and transverse striaa, is slightly dilated at the distal end, and then bevelled, 

 from the attachment of the terminal process to the point. The distal blades are longest 

 towards the upper third of the tuft, shorter dorsally, and shortest ventrally. Each is 

 flattened, slightly tapered, and curved distally, where it is bifid, with a secondary process 

 beneath. Oblique strias slope from the serrated edge of the blade downward and 

 backward. The bevelled base of the blade is attached by a web to the shaft. These 

 bristles, though pale, are finely iridescent, and in some are brownish in the posterior 

 region of the body. 



Comparing these bristles with those of L. Glaparedii (Plate LXXVIII, fig. 6) the 

 whole bristle is more slender, the tips are longer and more delicate, and the bifid tip is 

 more minute. The boldly bifid nature of the tip in L. Glaparedii and the more distinct 

 secondary process are in contrast with L. atlantica, the second or inferior spur being 

 curved and the secondary process adpressed. The serrations on the edge of the blade 

 are similar. The backward tilt of the bristle is seen in both, but L. atlantica has also a 

 tendency to a dorsal curve (i. e. a convexity toward the dorsal edge throughout). It is the 

 same type of bristle in both, but that of the abyssal species has been modified. It is the 

 same as that of Dalhousia atlantica of the ' Challenger,' l which agrees with this species 

 except in the absence of maxillae. Should these be found in fresh examples, then the 

 specific name given in the Annelids of the ' Challenger ' would stand. 



The ventral cirrus is of considerable length, slender, subulate, and tapering. It 

 extends a little beyond the fleshy part of the foot. 



Claparede found the male elements in L. Glaparedii developing in winter. None 

 have been seen in the present species. Eisig 2 notes the occurrence of hermaphrodite 

 glands in Hesione sictda, and cites the remarks of Claparede on Leocrates (Tyrrhena) to 

 show that such a condition may also occur in that species. The subject should be 

 re-investigated in living forms. In the same paper Eisig gives his views as to the caeca 

 of the gut of Leocrates (Tyrrhena,) having the function of a swim-bladder, but it cannot be 

 said that either structurally or physiologically these organs lend themselves to this 

 theory. 



What relationship the foregoing form or that of Claparede has to the various species 

 described or alluded to by De Quatrefages 3 is uncertain, for there is little that is definite 

 or that can be relied on in his treatment of the Hesionidae, as, indeed, Claparede long ago 

 pointed out. In the number of the tentacular cirri Leocrates (Tyrrhena) agrees, with the 

 genus Fallacia of De Quatrefages, but this is all that can be said with safety. 



Though the species had long been discriminated in my collection, the publication of 

 the Annelids of the ' Cauclan ' by Prof. Louis Roule gives his title priority. He correctly 

 describes the distinctions from L. Glaparedii in regard to the tentacular cirri and teeth. 

 His account of the dorsal bristles, however, requires further elucidation, for he states that 

 they are of two kinds — viz. a rare form, which is simple and delicate, tapering to a curved 

 point ; the other a camerated bristle, which at the tip has a cap of granular matter giving 



1 ' Annelids of the Challenger/ p. 186, pi. xva, figs. 5 — 7. 

 3 l Mitth. Zool. Stat. Neap./ II, pp. 298—300. 

 3 f Anneles/ pp. 95 — 111. 



