164 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [458] 
ure and migrate from one to another. Three species belonging to this 
group were taken at the surface with the towing-nets. The Lerneans 
are remarkable creatures, The females are generally very curious in 
form and very much larger than the more active and less abnormal males, 
and they are very low in structure, the reproductive system being enor- 
mously developed at the expense of nearly all the other organs. They 
live upon the exterior and gills of fishes, with the head deeply buried 
in the flesh, and subsist by sucking the blood of their victims. The 
Lerneonema radiatum (Plate VII, fig. 30) is very common on the men- 
haden, and is also found on the alewives. 
There are many kinds of parasitic leeches. One of the most remark- 
able is the Branchiobdella Ravenelii, (Plate X VILL, fig. 89.) This genus 
is peculiar in having broad, foliaceous, lobed or scolloped gills along 
the sides of the body. The large species figured was found several times 
on the large “ sting-rays,” several of them usually occurring together, 
on a large spot which had become sore and much inflamed by their re- 
peated bites. It is a very active species. 
The Cystobranchus vividus is a much smaller and quite slender leech, 
which has small, papilliform, whitish gills that alternately contract and 
expand along the sides of the body, each surrounded by a semicircular 
white spot. The colors are brownish or purplish, with three rows of 
small white spots on the back. This species is frequent on the common 
minnow, (Fundulus pisculentus,) in autumn and winter, and lives both 
in brackish water. and fresh water. With the last, on the minnows, is 
found another slender leech, destitute of gills; this is the Jchthyobdella 
Funduli. It has, like the last, four ocelli. The color is pale green with 
darker green and brown specks, often with whitish transverse bands 
anteriorly, and a white ring behind the head, at the constriction ; some- 
times there is a narrow pale dorsal line. 
A long, slender, sub-cylindrical leech, the Pontobdella rapax V., (Plate 
XVIII, fig. 91,) is quite common on the upper side of the “ summer- 
flounder,” (Chenopsetta ocellaris.) Itis avery active species, dark olive 
or brown in color, with a row of square or oblong whitish spots along 
each side ; the suckers are pale greenish white. The young are reddish 
brown, without spots. 
A species of Pontobdella was found adhering to Mysis Americana, 
near New Haven, May 5, in three instances, but whether this be its nor- 
mal habit is uncertain. 
The Malacobdella obesa.V. (Plate XVIII, fig. 90) is a large, stout, 
yellowish white leech, often two inches long, which is quite common in 
the branchial cavity of the “long clam,” (Mya arenaria.) 
The Malacobdella mercenaria V. is another similar species, but smaller 
and more slender, which lives in the same way in the “ round clam” 
(Venus mercenaria.) 
The Myzobdella lugubris is a small leech, which lives on the ‘ edible 
crab” (Callinectes hastatus,) adhering to the soft membranes between 
the joints and at the base of the legs. 
