164 THE ANNELIDES. ^ 154. 



entirely distinct from the rest of the body.® These suckers serve not only as 

 locomotive organs, as the one, for instance, which is situated at the posterior 

 end of the body, but also for the drawing in of liquid food, and particularly 

 Hood. For this purpose, many Hirudinei have a short and spacious pha- 

 rynx, possessed of muscular walls, which are blended with the parenchyma 

 of the body, and which are armed with horny teeth, by which they cause 

 the wounds necessary for sucking "the blood. With BranchiobdeUa, the 

 pharynx has horny upper and lower jaws, of a pyramidal form.''" With San- 

 guisuga, and Haemopis, on the contrary, the base of the pharynx has three 

 fleshy swellings, the projecting arciform border of which is edged with bicus- 

 pid teeth.''' In this respect, Clepsine is quite different. The pharyngeal 

 tube is very long, and from its base a movable fleshy tube can be protrud- 

 ed out of the mouth, and which the animal can use as a proboscis.''^' With, 

 the Abranchiati, and Capitibranchiati, the pharynx is simple, short and 

 muscular, and presents nothing remarkable. With the Dorsibranchiati, it 

 is very muscular, of variable length, and stretches freely into the cavity of 

 the body. By the aid of special muscles, it may be folded upon itself, and 

 project far out of the mouth. *'> With many Annelides, the pharynx has a 

 horny, masticatory apparatus of sometimes a very complicated structure,, 

 and which, when the pharynx is protruded, often extends out beyond it, and 

 serves as a prehensile organ.® These two, four, seven, eight or nine jaws 

 always move laterally upon each other. They are usually curved like 

 hooks, and denticulated upon their concave side. When numerous, they 

 are of dissimilar forms with the same individual.'^' 



IL Intestinal Canal. 



§154. 



The intestinal canal of the Nemertini passes directly from the mouth to 

 the anus, without forming a stomachal dilatation. Its walls are closely 

 united with the parenchyma of the body, and its internal surface throughout 

 is thickly set with annular folds, which, projecting far into the canal, form, 

 there pouch-like divisions. ''' 



3 Piscicola, and Pontobdella. tus of this organ are against this view, and quite i» 



4 See Henle, Multer's Arch. 1835, p. 575, Taf. favor of its being a pharynx. 



XIV. fig. 1. 8 The jaws are wanting with Amphinome, Phyl- 



5 See Moquin-Tandon, Monog. des Hirud. p. lodoce, Aricia, Chaetopterus, and Arenicola. 

 43, PI. I. fig. 2. 11, PI. IV. V. ; Brandt, Med. Zool. 9 Tliere are two strongly-curved jaws with iVe- 

 II. p. 245, Taf. XXIX. A. fig. 13-18, 21, Taf. reis, Lycantis, s.iv\ Peripatus iUmv with Polynoe, 

 XXIX. B. fig. 13-17. The swellings of these Aphrodite, a.r\A Glycera ; amlcvJiUl wAh Lumbri- 

 leeches are carried in front during suction, so as nereis. Of the seven with Eunice, there are 

 to resenal)le a three-rayed star — the form of the four, one on one side, and three on the other. The 

 wound which they proiluce. same asymmetry exists with those of Aslaura and 



6 See Hloi/ui'ii-Tiindon, loc. cit. PI. IV. This Oenone ; see A u do u in a.n(\ Mi/ne Edwards, Re~ 

 proboscis iiuitc n-niiinls one of the pharyngeal tube cherches, &c., loc. cit. 



ofthe P/arifiriiie,\v]iU:h also can be protruded from 1 According to firtVAA'^ (Danzig. Schrift, loc. cit. p. 



the mouth, but without being reversed. 96), these transverse folds do not exist with liorlasia 



7 This pharyngeal tube is short with Amphi- striata, except when the body is shortened by con- 

 nome. Nereis, Eunice, and Peripatus ; but very traction, and they disappear when it is again extend- 

 long with Aphrodite, Polynoe, llesione, Phijllo- ed. But it did not apjii^ar thus to me with the nu- 

 doce, Glycera, and Ooniada ; sec Audouin and merously folded intestine of Mecke/ia annutata. 

 Milne Edwards, licchvrches, kc.,\oc. cit. "ihniot Delle Chiaje had already observed these folds 

 Aphrodite, Polynoi, Amphinome, and otliers, with Polia sipunculus, but figured them as iso- 

 hae been regarded as a stomach ; see Treviranus. lated pouches (Memorie, loc. cit. II. p. 407, Tav. 

 in Tiedemaiin's Zeitsch. f. Phys. III. p. 161. Taf. XXV III. fig. 3, 6, or Isis, 1832, Taf. X. fig. II. 3, 

 XII. fig. 9. 10, k ; Grube, Zur Anat. d. Kiemen- 4). According to (^uatre/afres (Ami. d. Sc. Nat. 

 Würmer p. 54, et seq. and Stannius, Isis, p. 982. VI. 1846, p. 243), the intestinal canal of tha 

 But the position, structure and muscular appara- Nemertini, which occupies the axis of the body. 



