3S0 Mr. II. A. Baylis on Inluililants of 



nssevt tliat Gecarcoidea lalandii, tliongh apparently a move 

 laml-loving species, never enters fresh water. 



In anv case, however, whether the e<»;gs were deliberately 

 dopositeil ill or near the gill-chambers by the t'emale Hy, or 

 whether the larva; subsequently wandered into them, either 

 accidentally or following some regular instinct, they would 

 appear to have thriven there, and it is suggested as at least 

 a possibility that tliey derived sustenance from the blood of 

 the crabs, their chitinous "jaws" enabling them to puncture 

 the epithelium of the gills or of the vascular lining of the 

 chamber. 



With regard to tlie Oligoclinete worms, the case is even 

 more puzzling, as they have not even jaws, nnd it is difficult 

 to see what food, except, perhaps, mucus, they can obtain in 

 such a habitat. The remarks made on this head concerning 

 Knchytrmus carcinopJdlus [2, p. 14] apply equally to the 

 present species, which 1 now proceed to describe. 



Enchytrceus parasiticus, sp. n. 



This form is evidently very closely related to the species 

 {E. carcinophilus) described by me from the gill-cbambers of 

 Gccarcivus lagostoma [2]. It differs from it, however, in 

 certain features sufficiently to constitute a distinct species. 

 In size it is considerably smaller than E. carcinophilus^ 

 measuring only 8-9 mm. in length, or about one-quarter of 

 the lengtli of a iull-grown specimen of the larger f^pecies. 

 Its thickness is about 0*35 mm. The number of segments in 

 several specimens in which they were counted was found to 

 vary between 69 and 82. 



The chaetai are arranged, as usual, in 4 bundles to each 

 segment, but there are invariably only 2 cha^tse in each 

 bundle; they are simple, pointed, and straight. Segments i. 

 and xii., as in the otlur species, are without bristles. 



There is a very marked ventral flexure of the anterior end 

 of the worm, the prostomium being bent down into a vertical 

 position, and the mouth being therefore quite ventral. This 

 peculiarity was not observed in E. carcinophilus, but in the 

 present species is so constant a feature that the specimens 

 invariably lie on their sides, and can only with considerable 

 difficulty be mounted in any other position. 



The clitellum is very feebly developed as compared with 

 the larger species, it is, in fact, very inconsijicuous, but 

 can be made out as a very slight thickening, containing 

 glandular cells, extending from about the middle of seg- 



