THE CIRRATULID3Z. 



235 



fluid. The Ammocharidse have long segments, with a crown of ramitied lobes in front, and their 

 digestive apparatus is within the sanguiniferous system ; and the Aricidne with a slightly depressed 

 round body, made up of numerous short segments, have the head without tentacles and cirri, but the 

 buccal ring carries dentigerous tubercles. They have short lanceolate or filiform branchiae, and a short, 

 very slightly contractile proboscis. 



FAMILY CIRRATULID.E. 



The genus Cirratulus is characterised by its sub-cylindrical vermiform body being composed of 

 numerous narrow segments, and by its conical head being small, and generally deprived of tentacles. 

 The feet are small, and form a double series along each side. The branchiae are very peculiar, resemble 

 cirri in their general appearance, and show themselves as long, filiform, tortuous filaments, springing 

 from the back or margins of the segments. The form of the body of these worms is very like that of 

 the Earth Worms (Lumbrici), to which they were referred by the earlier writers. One of the 

 commonest species of Cirratulus on English shores is the Northern* Cirratule, found on several 

 parts of the southern coasts, such as Devonshire and Cornwall. It varies from three to six inches in 

 length, and individuals even nine inches long are occasionally found. The body is rather less than a 

 goose-quill in calibre, of a brown or yellowish colour. The head is very small, the segments of the 

 body very numerous, and the branchial filaments are found in greater abundance near the head 

 than on the body. It lurks under stones, in a somewhat muddy soil, in which it forms burrows 

 similar to those of the Earth Worm, and into which it retires slowly, when disturbed. The filaments 

 by which it is so remarkably distinguished, and which curl around it like so many parasitical worms, 

 are the branchiae, or organs through the medium of which the blood is exposed to the influence of 

 the air, and fitte J for the purpose of life. So says Dr. Johnston ; and in further describing these 

 organs, he tells us that each consists of a large central vessel carrying red blcod, surrounded by 

 a white gelatinous transparent membrane, and that they are consequently of a fine red colour. The 

 setae of the feet are of two kinds. The upper, or superior bundle, is composed of about six three 

 long and slender, and three shorter, but comparatively stout and all simple, unjoin ted, and acute. The 

 inferior bundle has only three in the upper segments, diminishing to one only in the caudal extremity, 

 and all stout and curved, according to Dr. Johnston, like the italic letter f. A more beautiful species 

 than the one just mentioned is called the Tentacled Cirratulus, and is possessed of very numerous 

 branchial filaments throughout the length of its body. It is four inches long, rather narrowed 

 in the middle of the body, and consists of nearly 230 segments. The colours of this species 

 aro more brilliant than those of Cirratiihts borealis. Another of the Cirratulidaef is an in- 

 habitant of the shells of Cyprina islandica, one of the hardest and most compact of British shells. 

 It lives in a straight or slightly sinuous furrow drilled in the shell. The worm fits the furrow 

 exactly, and when under water it gradually protrudes the tentacles and filaments from the circular 

 aperture. The filaments are laid along the shell, and either kept quiet or in slight movement. It is 

 about an inch long and scarcely a line in diameter, and how it makes the hole and channel in the 

 shell is certainly a great 

 puzzle. It lives on the 

 British coasts. 



The four - horned 

 Spio,J with a long 

 slender sixty - jointed TROPHONIA PLUMOSA. 



tapering body, termi- 

 nating in two short styles, and with long cirri and two very long tentacles on the head, near four 

 black eyes, is a member of the family Spionidae. It is pale in colour, and has pink cirri, and makes 

 a very slender tube composed of adventitious matter slightly agglutinated together, and placed 

 usually on Sertularian Zoophytes. Amongst this family are some remarkable forms, which have not 

 only internal ovaries, but also external ones like bunches of grapes in shape (genus Lepidoceras). 



A small worm, from six to eight lines in length, worm-like in shape, with a small head and two 



^ * Cirratulus bwcalis. f Dodccaccria conchonun. 



J Spio quadricornis. 



