638 DESCEiPTiON OF [Eotatoriu' 



for observing its internal structure, but the limits to wliich I am 

 restricted preclude my entering into its interesting details. Length 

 l-96th. 



!N'oTOM3iATA tubci. — Bodj conical, trumpet- shaped, dilated ante- 

 riorly ; foot fiu'cated and acute. It resembles, in form, Stentor Mullen, 

 but is more active. Length 1-1 20th. 



I^. hrachionm. — Body dilated, nearly square, depressed, foot slender, 

 eggs pendulous. This creature appears to have a shell, but Dr. E. 

 says it has not : N. gnmularis, as before remarked, lays its eggs upon 

 it. Length l-96th. 



N. iripus. — Body oval, sub-truncated, and slightly auricled in 

 front ; it has a short, styliform, true tail, and forked foot. Length 

 l-200th. 



IsT. saccigera. — Body elongated, cylindrical, attenuated posteriorly ; 

 fork short. It has a curious internal pouch beneath the eye ; vibra- 

 tile organ lateral, as in Pleurotrocha. Length 1 -144th. 



N. copeus. — Body large, attenuated at both ends j tail small, and 

 indiu'ated. This curious creature has a long bristle on each side 

 of its body ; and on each side of the head a stout branch, called, by 

 Dr, Ehrenberg, an auricle, having vibratile cilia around the ends, 

 and, like the setae, standing out, so as to appear like a cross ; a thick 

 gelatinous substance covers the body ; the back terminates in a some- 

 what hard point, which is a true tail, between which and the foot 

 the discharging opening is situated. When creeping, the large vibra- 

 tile arms are withdrawn, but it vibrates with the frontal ciHa and 

 proboscis. Fig. 416 represents the creature extended. Length 1 -36th. 

 N. ceiitrura. Body large, attenuated at both ends ; tail small, 

 indurated ; auricles small, and no lateral setae present. It is often 

 enveloped in a thick slime, in which articulated threads of Hygro- 

 cocis vegetate, giving the animal a hairy appearance. It swims 

 awkwardly. Length l-36th. 



N. hrachyota. — Body small, slightly attenuated towards the ends ; 

 no tail, auricles very small ; it has two dark spots near the eye ; 

 foot forked. Length 1-1 20th. 



N. Pleurotrocha. — Body slender, cylindrical, not auincled ; foot 

 with very short toes ; eye obscure, ovate, largo ; jaw with one tooth. 

 Length 1- 144th. Berlin. Has the form of iYe«<>'o^;-oc7<ff. 



