It differs from the preceding in several respects, being larger, the body thicker, and more cylindrical; the lower part truncated, with two short diverging points projecting from the middle. It was found in a ditch containing plenty of duck-weed.
136. Cercaria Lupus.
C. cylindrica, elongata, torosa cauda spinis duabus. [Plate XXV.] Fig. 39. Cylindric cercaria, long, the tail furnished with two spines.
This animalculum is larger than most of the cercarias, and in some particulars resembles the vorticella. It is full of muscles, capable of being contracted or extended; cylindric, composed of a head, a trunk, and a tail; the head is larger than the body, the apex turned down into a little hook; the tail is like the body, but narrower, terminating in two very bright spines, which it extends in different directions; sometimes it contracts itself into one half its common size; and again extends itself as before. It was found in water among duck-weed. a the head, b the trunk, c the tail, d d the spines thereof.
137. Cercaria Vermicularis.
C. cylindrica annulata, proboscide exsertili, cauda spina duplici. [Plate XXV.] Fig. 40. Cylindrical, annulated, with a projecting proboscis, two small spines for the tail.
It is a long, cylindrical, fleshy, mutable animalculum, divided into eight or nine rings, or folding plaits; the apex either obtuse or notched into two points; the hind-part rather acute, and terminating in two pellucid thorns, between which a swelling is sometimes perceived. It often projects a kind of cloven proboscis. It is found in water where duck-weed grows. d d the points of the fore-part, e the proboscis.
138. Cercaria Forcipata.
C. cylindrica, rugosa, proboscide forcipata exsertili, cauda bicuspidata.
Cylindrical cercaria, wrinkled, with a forked proboscis, which it can extend, or retract. It is found in marshy situations.