400 BOTIFERA. 



the blood enters. Pontoltdella muricata L..on Rays. Branc hellion torpedinis 

 Sav., Clepsine Sav., (Clcpsinidce}, Cl. Uoculata Sav., Cl. complanata Sav., CL 

 marginata 0. Fr. Mull. Hcementaria mexicana de Fil., H. officinalis de Fil., 

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

 GMlanii 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. Hirudo 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 casca, of which the last pair is 

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

 the variety distinguished as officinalis, possesses 80 to 90 fine teeth on the free 

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

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

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

 to attain sexual maturity. Ilcemopsis vorax 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. Aiilastomum gulo Moq. Tand. Also known as the horse- 

 leech, feeds on Mollusca, Nephelis Sav., N. vulgaris Moq. Tand. 



Fam. Brancblobdellidae. 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. Branchioldella parasita Henle, B. astaci Odier. 



CLASS IV. ROTATORIA * = ROTIFERA. 



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

 with 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 fiotifera is 

 certainly externally segmented and divided into more or less sharply 



* Ehrenberg, " Die Infusionsthierchen als vollkommene Organismen," Leipzig, 

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

 Phil. Trans. Roy, Soc. 1844. Fr. Leydig, " Ueber den Bau unddie systematische 

 Stellung der Raderthiere,'' Zcitsclir. fur wiss. ZooL, Bd. VI.. 1854. F. Cohn, 

 "Ueber Raderthiere," Zeitschr.fur wiss. Zool., Bd. VII., 1856, Bd. IX., 1858, 

 Bd. XII., 1862. Gosse, " On the Structure, Functions and Homologies of the 

 Manducatory Organs of the class Rotifera," Phil. Trans., 1856. W. Salensky, 

 " Beitrage zur Entwickelungsgeschichte des Brachionus urceolaris," Zcitsclir. 

 filr wiss. ZooL, Tom. XXII., 1872. 



