HOMOLOGIES. 137 



Genus VIII. Micrura, Ehrenberg.— Characters as in Linens, with the addition of a soft, filiform 

 caudal process, capable of attachment. 



1. M.fu8ca,Ti. s. — Eyes small, from four to eight on each side; body much flattened and 



thinned at the edges ; caudal process often moniliform ; colour pale brown or yellowish, 

 speckled with brownish grains, especially in front. 



2. M.fasciolata, Ehrenberg. — Eyes marginal, placed towards the anterior part of the snout ; body 



various shades of brown, generally barred with white belts. 



3. M. purpurea, Dalyell. — Eyeless. A bright yellow patch at the tip of the snout; body of a 



uniform rich dark brown colour. 



4. M. aurantiaca, Grube. — Eyeless. A white patch at the tip of the snout ; body rounded and of 



a fine brick-reel hue. 



Genus IX. Meckelia, Leuckart. — Structure of the rounded body-wall as in Lineus. Cephalic 

 fissures absent. Proboscis furnished with only three coats, viz. external spiral, longitu- 

 dinal, and glandular. 



1. M> asulcata, n. s. — Eyeless. Body thick and round; of a uniform pinkish hue. 



Family III. Carinellid.e. — Lateral nerves placed between the basement-layer of the cutis and 

 the external (circular) muscular coat of the body- wall, or in the substance of the 

 longitudinal layer close to the circular. There are only two muscular coats. The pro- 

 boscis has four layers, viz. external elastic, circular, longitudinal and glandular. 



Genus X. Carinella, Johnston. — Body elongated, tapering from the front backwards. Snout 

 wider than the rest of the body, bluntly rounded in front ; mouth sometimes small. 



1. C. annulata, Montagu. — Eyeless, with a white patch on the snout ; body round, of a rich 



red colour, striped longitudinally and banded across at somewhat regular intervals with 

 white belts. Rarely pinkish throughout. 



2. C. linearis, Montagu, MS. — Eyeless. Head spathulate, somewhat pointed in front; milk- 



white. 



Genus XL Valencinia, De Quatrefages. — Structure of the proboscis as in Carinella. The 

 lateral nerves lie in the longitudinal muscular coat of the body-wall. The snout is shaped 

 as in Lineus lacteus, and furnished with a row of eyes on each side. The mouth forms a 

 distinct fissure a considerable distance behind the ganglia. 



1. Valencinia lineformis, n. s. — Roseate in front, yellowish white posteriorly. 



Family IV. CephalothriciDjE. — Commissures of the ganglia separated by a distinct antero- 

 posterior interval. Lateral nerves placed between the longitudinal muscular coat and an 



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