INFTTSOETAl ANIMAICUIES. 77 



selves, but far inferior in type, to that of the females, in every 

 structure, save that devoted to the continuation of the species. 



The discoverer (Mr. Brightwell) of the male beings, could distia- 

 guish no jaws, gullet, stomach, nor hepatic organs, and, indeed, no 

 appearance of extraneous matter being received into the body. Mr. 

 Gosse, in describing the male Asplanchna, says : — " the place of the 

 stomach was occupied by a long sac, having a slender neck, origina- 

 ting from the fi'ont part of the head mass, and, at the bottom, 

 broadly attached to the sperm-bag." (Plate XV, fig. 65, 66, and 

 Plate XXIII, fig. 7, 8.) 



Section XXII. — Of the Vascular and Respiratory system of the 

 Rotatoria. — The vascular system in these animals, according to 

 Siebold, is most probably one circulating only water, and which, by 

 its organization and character, must be also considered to serve a 

 respiratory purpose. There exists, for instance, in most Rotatoria, 

 on each side, a small band-like organ, through which an apparent 

 vascular canal winds. At the anterior extremity, these two side 

 bands, with their contained vessels, become connected with other 

 short lateral vessels, which open directly into the abdominal cavity, 

 having their orifices fornished with fi-eely oscillating or vibratile 

 flaps. The number of vibratile orifices varies in different species, 

 and, it would appear, even in different individuals of the same 

 species. Usually, two or three are met with on one side, and from 

 five to eight on the other ; but, in not a few, a much greater number 

 exists, as in Notommata clavulata, and JS". myrmeleo, while in the 

 genus Flosmlaria, Dr. Dobie states the tremulous giU-hke organs to 

 be absent. (Plate XXIII, fig. 6, 9.) 



At the posterior part of the body, the two side bands approach 

 and unite in a common thin- walled trunk or contractile sac, which 

 by its active contractions, forces out its fluid contents through the 

 cloaca! opening. 



In the neck of most Rototaria, is also placed a projecting tubular 

 process, sometimes two, through which, in aU probability, the water 

 enters the interior of the body, and passes into the water-circulating 

 system just described. Admitting the tube to have the office 

 assigned it, it may be justly called the respiratory tube. Mr. Gosse 

 is led to regai'd tubes or processes of this character rather to be 



