143 



XXV. — On the Notommata parasita (Ehrenb.), a Rotiferous Animal 

 inhabiting the Spheres of Volvox globator. By P. H. Gosse, Esq. 



(Read December 11, 1850). 



This interesting form was made known in 1835, by Professor 

 Ehrenberg, who has given a brief note of its singular parasitic 

 habits. It first fell under my own notice on the 26th of June, 1850, 

 in water kindly given to me by Alfred Eosling, Esq., of Camberwell, 

 and taken, as I understand, from a reservoir in his grounds. I af- 

 terwards obtained it on the 8th of July following, from a little pool 

 near the Eailway Station at Leamington, Warwickshire. 



No cognizance of this animal is taken by the unassisted eye, for 

 its greatest length (so far as I have observed) is -j-^ of an inch. The 

 body is somewhat cylindrical, terminating in a blunt point behind, 

 without any foot or toes that I can perceive. When the stomach or 

 ovary is distended, the form is swollen. The gizzard is large and 

 long ; not perfectly symmetrical, the point (as is not infrequent in 

 the Hydatineous family) being rather on one side. It contains a 

 long incus, which seems to have a forked summit, on which work two 

 apparently simple mallei, the one long and nearly straight in the rod, 

 the other shorter and bent inward (see Plate XX. fig. /.) The points 

 are capable of being protruded from the mouth (see fig. e). By 

 means of the compressorium, the forked summit of the incus was 

 found to be separable from the rod (as seen at i), and to be furnished 

 with a square umbrella, delicately membranous, of two (perhaps four) 

 points. A wide conical alimentary canal, apparently simple, is sepa- 

 rated by a long duct from the gizzard, and carries two oval pancrea- 

 tic glands. The canal tapers to a narrow orifice at the cloaca, which 

 is placed at the extremity of the body. The usual occipital sac car- 

 ries a large eye of a rich crimson hue, set on its dorso-posterior end, 

 like a wart. The venter is as usual occupied by the ovary, some- 

 times containing only clear nuclei (fig. c) ; at others, a large opaque 

 granulated egg in process of development, (fig. e). A small contrac- 

 tile bladder, whose intermissions are rather longer than usual, is 



