No. 2.] A NEW MARINE TRICLAD. 169° 
limuli, v. Graff’s paper is a brief but valuable anatomical con- 
tribution, to which I shall have occasion to refer again. 
It is my opinion that there are at least three distinct 
species of Triclad to be found on Limulus. All the descrip- 
tions to which I have alluded are, I believe, referable to the 
commonest and largest of these species, and for it I shall 
rétain the name Bdelloura candida, following the example of 
Verrill (73, p. 634). Another species, which I propose to call 
Bdelloura propinqua, is about 8 mm. long, being about half as 
large as the full-grown B. candida. A third species, still 
smaller (only 2-3 mm. long and .3—.4 mm. broad when fully 
expanded), differs considerably from the species of Ldelloura, 
so that I have concluded to erect a new genus for its accom- 
modation —the genus Syucelidium.1 When not otherwise 
stated, the description in the following paper applies to this 
last species, to which I give the specific name pellucidum. 
The existence of more than one species of planarian on 
Limulus was first suspected by Ryder (822). He inferred 
that there might be three species, from three well-marked 
types of egg-capsules which he found on the gills. That he 
saw one of the species of Bdelloura (probably a half-grown 
candida) is shown by his Fig. 8. His Fig. 10 is undoubtedly 
taken from a specimen of Syucelidium pellucidum, as is shown 
by the fusion of the posterior gut-rami. In concluding his 
article, Ryder says: “I do not propose to name the species, 
as these supposed distinct life-histories may, after all our 
endeavors to separate them, be only phases of the same 
thing.” 
S. pellucidum was also seen by Gissler (82), as is evident 
from his Fig. 1. He regarded it as the young of B. candida, 
an error into which he need not have fallen, had he carefully 
examined the reproductive organs. He seems, however, to 
have had no clear conception of these organs in Triclads, for 
he designates the two uteri as sexual glands in his Fig. 1, and 
in the text remarks: “From analogy I infer the latter to be 
the male organs, the female glands having escaped my obser- 
1 From cvy, together, and xoudioy, a little intestine, in allusion to the confluence 
of the posterior gut-rami. 
