824 DR. W. A. GUNNINGTON ON PARASITIC 
contrast the form sharply with the typieal species of Lerncocera, 
and which might serve as a claim to more than specific dis- 
tinction. 
It might be well to indicate here, briefly, the other forms 
which in my judgment differ materially from the more normal 
members of the genus. ‘The species L. lagenula, as described 
and figured by Heller, retains in a great measure the primitive 
segmentation of the body which is usually lost, and at the 
same time fails to show the pre-genital prominence and charac- 
teristic boot-like shape of the posterior end. It has also under- 
gone a very slight amount of torsion. The North American 
form L. pomotidis shows, according to the figure, a complete 
absence of any torsion, though otherwise it might rank as_a 
typical Lerneocera. Finally, it must be admitted that the form 
to be described below as L. diceracephala exhibits certain features 
which are non-characteristic, and one feature which is not 
shared by any other species of the genus. This peculiarity, to 
which reference is made in the specific name, is the existence 
of only two cephalic horns—apparently the dorsal pair—ainstead 
of four. Beyond this, the lobed nature of the body, suggestive of 
segmentation, and the apparent absence of any torsion, are 
further points of distinction. 
Key to the Species of LERNZOCERA. 
a. Single pair of cephalic arms present ...........0..0000ce:csseeeeesee. iceracephala. 
a’. Cephalic arms markedly asymmetrical, three in number ...... catostomi. 
a’. Two pairs of cephalic arms present. 
b. Cephalic arms simple without any indication of forking. 
c. Ventro-lateral tubercles present behind junction of 
ALIS PATIO MO CaVuaR GAS eee eee ante aew select sina dectressee mentees 
ce’. No ventro-lateral tubercles present. 
d. Cephalic arms very long and straight; body 
terminating in three broadly-rounded tubercles. pomotidis. 
d’. Cephalic arms of moderate length, curved for- 
wards; body terminating in five rounded 
haplocephala. 
_ tabercles oie eee eects eetieeterreees Oructata. 
b’. Cephalic arms forked. 
c. Pre-genital prominence absent ...............cccee eee Lagenula. 
c’. Pre-genital prominence present. 
d. Dorsal cephalic arms simple; ventral arms with 
ROCESS MRR ee erence eset Pr ula eatamntat das sa sinhc om 
d’. Dorsal cephalic arms forked ; ventral arms simple. 
e. Ventral cephalic arms nearly as stout as 
dorsal arms; egg-sacs oval, +4 length of 
HOKaGl\//sapasees obs terfonn oat ek masmcebe cba cemebance Camhee 
e’. Ventral cephalic arms much more slender 
than dorsal arms. 
Ff. Dorsal cephalic arms T-shaped ; egg- 
sacs cylindrical, 3-4 length of body ... eyprinacea. 
J’. Dorsal cephalic arms Y-shaped......... temnocephala. 
phoxinacea. 
esocina. 
1. LERN#ZOCERA DICERACEPHALA, sp.n. (PI. I. figs. 1-3.) 
Description.—(Adult female.) Cephalic arms only two in 
number, of considerable length and projecting laterally from the 
region of the head-tubercle at about right angles to the body. 
