400 BOTIFERA. 



the blood enters. PontolxJi-Uit mvricatn L., on Kays. Brancliellion torprdiitis 

 Say., Clepainc SaY., (Clepsinidce\ Cl. bitn-nliitu Sav., ('I. roiiiplatiatu Sav.. CL 

 miiri/iiinta O. Fr. MiilJ. Ihrinrtttu ria nir.r/c// tt,t de Fil., //. officinal ix de Fi].. 

 both in the Lagunes of Mexico, the latter used for medicinal purposes. H. 

 Ghilanii de Fil.. in the river' Amazon. 



Fam. Gnathobdellidae. Leeches with jaws. Pharynx armed with three fre- 

 quently serrated jaws, and folded longitudinally. In front of the mouth there 

 is a ringed, spoon-shaped process, which forms a kind of oral sucker. The 

 cocoon has a spongy shell. Jlirudo L. Usually with 95 distinct rings, of which 

 four are upon the spoon-shaped upper lip. The three anterior rings, the fifth 

 and the eighth, bear the five pairs of eyes. The male genital opening lies between 

 the 24th and 25th, the female between the 29th and -30th rings. The three 

 jaws are finely serrated and can be moved like a circular saw in a manner 

 well adapted to inflict a wound, which readily heals, in the external skin 

 of man. The stomach has eleven pairs of lateral cieea, of which the last pair is 

 very long. The cocoons are deposited in damp earth. //. medicinalis L., with 

 the variety distinguished as nffirinul is. possesses 80 to 90 fine teeth on the free 

 edge of the jaws ard attains a length of about six inches. They were 

 formerly common in Germany and are still frequently to be found in Hungary 

 and France. They are cultivated in special ponds and take three years 

 to attain sexual maturity. Ha-niojjxix vont.i' Moq. Tand, the horse-leech. 

 30 coarse teeth on the edge of the jaws, which enable it to inflict wounds on 

 soft mucous membranes. The horse-leech is indigenous in Europe, and espe- 

 cially North Africa. It attaches itself to the interior of the pharynx of horses, 

 cattle and men. Anlastmniim yulo Moq. Tand. Also known as the horse- 

 leech, feeds on Mollusca. ycplu'lix Sav.. JV. rult/itrix Moq. Tand. 



Fam. Branchiobdellidse. The body in the extended condition "is nearly 

 cylindrical and is composed of few unequally ringed segments. There is a 

 bilobed cephalic lobe without eyes, with a well-developed sucker at the posterior 

 end of the body. Pharynx without proboscis, with two flat jaws lying one 

 above the other. Bnuicli'ioliilcHu jxirnxif/i Henle, B. astari Odier. 



CLASS IV. ROTATORIA * = ROTIFERA. 



With a retractile ciliated apparatus at the anterior end of the body, 

 wit/t cerebral ganglion and excretory canals-; without heart or true 

 vascular system. The sexes are separate,. 



The Rotifera are Worms which can be derived from Loven's larva 

 and have nothing to do with the Arthropoda, since they are without 

 limbs and do not develop metameres. The body of the Rotifera is 

 certainly externally segmented and divided into more or less sharply 



* Ehrenberg, ' Die Inf usionsthierchen als vollki >mmene Organismen;" Leipzig. 

 1838. Dujarctm, " Histoire naturelle des Infusoires," Paris. 1841. Dalrymple, 

 Phil. Tninx. Hoy, Soc. 1844. Fr. Leydig, ' Ueber den Bau unddie systematise-he 

 Stdlung der Kivderthiere," Zr'itxdn: fur MV.V.V. Zool.. Ed. VI.. 18o4. F. <A>hn, 

 "Ueber Radt-rthiere," Zetxchr. fiir wis*. ZvoL. P.d. VJl., 1856. Bd. IX., 1858, 

 Bd. XII.. 18(>2. Gosse, " On the Structure, Functions and Homologies of the 

 Manducatory Organs of the class Rotifera,"/'///'/. Trait*., 1856. W. Salensky, 

 ' Beitriige xAir Entwickelungsgeschichte des Brachionus urceolaris," Xcitxclir. 

 fiir n-i*x. Ziwl.. Tuin. XXII.. 1872. 



