Brancheli.id^.- 



-ANNELIDA.- 



- Phtllisid.?:. 



301 



issue at the apijroacli of spring. The suctorial Anne- 

 lides do not possess the power of reproducing amputated 

 portions of their body like the Lumhricida:. They are 

 oviparous, and protect their ova in heavy capsules 

 or in fibro-gelatinous cocoons. The young do not un- 

 dergo any metamorphosis, and attain maturity slowly. 

 Progression is effected by alternate fixations and loosen- 

 ings of the suckeis, and by corresponding contractions 

 and extensions of the intermediate segments or rings. 

 Many species can also swim in the water by undulatory 

 eel-like movements of the extended body. 

 This order contains several families. 



Family I.— BRANCHELLID^. 



The species of this small family have the oral sucker 

 entire, and the body is furnished with brancbia^form 

 lobes or membranous appendages on each side of the 

 segments, which appear to serve the purpose of respira- 

 tion — aerating, according to Quatrefages, the lymph and 

 chyle previous to their admixture with the blood. 



Family II.— PISCICOLID.a: {Fish-leeehcs). 



The species of this family do not possess the mem- 

 branous branchiseform lobes on the segment, which the 

 preceding family has. Their jaws are wanting or are 

 reduced to three projecting points. They live parasiti- 

 cally upon the bodies of fishes, on whose juices they feed. 

 Some species are peculiar for the strong tincture or 

 colour whicli they impart to the spirits in which they 

 are preserved ; Pontuhdella Iccvis, for instance, impart- 

 ing a beautiful scarlet colour, while P. muricahi tinc- 

 tures the fluid with an intense green. 



Family III.-NEPHELID.E. 



This family of worms contains a number of species 

 which have the oral sucker incomplete, continuous with 

 the body, and formed by a moulding of the anterior 

 rings. The mouth is destitute of jaws, or they are, 

 when present, rudimentary ; the anus is large, and the 

 gidlet is long. This rudimentary condition of the jaws 

 disables the species belonging to this family from pierc- 

 ing the skin of animals. They are the carnivorous 

 members of the order Snctoria ; preying on worms, 

 mollusks, larvce of insects, &c., which they generally' 

 swallow entire. The species are all lacustrine, are not 

 found parasitic, but swim with ease through the water, 



or crawl like other Annelides, along the ground. M. 

 Audouin says, that they appear to possess something 

 iu their structure which makes them afraid of the con- 

 tact of air, that they never voluntarily quit the water, 

 and even perish soon after leaving it. Dr. Johnston, 

 however, asserts that they often leave the water, and 

 take up their abode on stones on the wet shore. 



Family IV.— HIKUDINID^ {The True Leeches). 



This family contains, amongst others, the two well- 

 known species called the Medicinal and Horse Leech. 

 The family is eminently suctorial in their habits; their 

 mouth is armed with three jaws, by means of which 

 they cut into the skin and suck the blood of vertebrate 

 animals, only falling off' when gorged. The alimentary 

 canal in the leeches is deeply incised and lobed, with 

 tlie hinder pair of lobes elongated like intestines. In 

 these the blood which they have sucked remains for 

 days and weeks, or even months without digesting or 

 passing into the intestine, and what is curious, without 

 coagulating, retaining in fact its fluidity during the 

 whole of that time. They are enabled to endure absti- 

 nence for a length of time, without experiencing any 

 loss of bulk. Leeches are inhabitants of fresh water 

 ponds and ditches, but they often leave the water of 

 their own accord for a length of time. In winter they 

 disappear, and remain hidden during the continuance 

 of the cold weather. The ova are deposited in a curious 

 cocoon, which closely resembles a sponge. 



Family V.— GLOSSOPORID2E. 



" These are small and neat leeches, usually so trans- 

 parent as to permit the disposition of the viscera to be 

 seen without any dissection." — {Johnston.) They are 

 of little general interest. 



Family VI.— PHYLLINID^E. 



The animals belonging to this family have frequently 

 been arranged along with the Entozoa or Intestinal 

 Worms. They are external parasites, being found on 

 the outer surfice of marine fishes and ilullusca. The 

 body is oblong, flattened, but not divided into segments; 

 there is no distinct head, and no eyes. The mouth is 

 without teeth or proboscis, but has usually a small suc- 

 torial disc on each side of it, and the posterior extremity 

 is furnished with a large circular suctorial disc. 



