13° LACINULARIA SOCIALIS 



cceca projecting from its outer surface. Within it is clothed with 

 very long cilia. 



The intestine is short and wide, and comparatively delicate ; it 

 bends suddenly upwards on the side opposite the mouth, and termi- 

 nates in a cleft of the integument, whose whole extent it did not seem 

 to me to occupy. (Fig. i k?) 



The Water Vascular System. — This s}'stem is thus loosely and 

 confusedly alluded to — I cannot call it described — by Professor 

 Ehrenberg ; i — " The vascular system consists of transverse circular 

 canals in the bod)-, a vascular network at the base of the wheel-organ, 

 with perhaps a broad circular canal at this part, and of trembling 

 gill-like bodies " — {loc. at. p. 403). The vascular system is so 

 obvious,'' that it is difficult to understand how it can have been thus 

 blurred over. 



The reader will bear in mind that the two bands which run up 

 from the cloaca in many Rotifera, and are usually connected at their 

 extremity with a " contractile vesicle," while they give attachment 

 in their length to the " trembling gill-like organs " of Ehrenberg, are 

 considered by the latter to be the testes. He says that " the trem- 

 bling organs '' appear to be within the sac in Hydatina, outside it in 

 Notominata. 



Von Siebold (' Vergleichende Anatomie ') first pointed out that a 

 vessel runs up in each of these bands, and that the " trembling organs " 

 are short branches of these vessels, each of which contains a vibrating 

 ciliary band (Flimmer-lappchen), to which the trembling appearance 

 is due. According to Von Siebold each of these vibrating bodies 

 indicates an opening in the vessel. 



Oskar Schmidt (' Versuch einer Darstellung d. Organisation d. 

 Raderthiere ' — Erichson's Archiv. 1846) asserts that the ends of the 

 water-vessels are closed, and that the vibrating body is within them. 



Dalrymple {loc. cit.) saw no testes in the lateral bands of Notom- 

 viata, and considers that the " tags " (the " trembling organs '' of 

 Ehrenberg) are externally ciliated at their extremities. 



Mr. Gosse ('Microscopical Transactions,' 1851) describes the 

 water-vascular system in Notominata aiirita, and states that the 

 "tags" of Ehrenberg are really pyriform sacs; but he seems not to 

 have distinguished the contained cilium — at least his description is 

 ambiguous. " When trembling moderately they are seen to be little 

 oval bags attached to the tortuous vessel by a neck and sac at the 



' " I can thus affirm, that what Ehrenberg describes as vessels in Lacinularia are, in fact,, 

 not vessels at all." — Leydig, loc. cit. p. 463. 

 ^ Sehr aus-geprafjt, Leydig, p. 465. 



