42 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
American Terrestrial Leech.* — Mr. S. A. Forbes calls attention to 
a hitherto unnoticed species of terrestrial leech occurring commonly in 
Illinois, where it is found in moist earth. When first found it was 
regarded by Prof. Yerrill as identical with bis Semiscolex grandis , but is 
certainly distinct from it, and may be called S. terrestris sp. n. We may 
suggest that this hybrid generic name be altered to Hemiscolex. Con- 
tracted spirit specimens have a length of 7 in., are 3/4 in. wide, and 
3/8 in. deep. The colour is sooty drab varying to plumbeous black, 
and rather lighter beneath ; a well-defined darker median longitudinal 
stripe is almost invariably present. There is no external trace of 
segmental papilla. In all there are one hundred and four annuli. The 
eyes are ten in number ; the male sexual orifice is on the twenty-eighth 
entire annulus, in the female on the thirty-third. The three maxillae 
are rudimentary, and have an ill-defined armature of teeth. The only 
known food of this leech consists of earthworms of various genera, and 
these it swallows entire. Like the earthworm, this creature probably 
penetrates to considerable depths during the dry weather of mid- 
summer. 
Anatomy of Sipunculus Gouldi.f — Mr. E. A. Andrews gives a full 
account of the anatomy of Sijpunculus Gouldi , which agrees closely with 
that of S . nudus ; it is also sufficiently similar to that of Phymosoma as to 
indicate the fundamental identity of the two genera in all but secondary 
characters. The body-wall of S. Gouldi has, however, a less specialized 
epidermis than the other Sipunculid, while its glandular bodies are 
essentially identical with those of Phymosoma. The peculiar arrange- 
ment of the gland-cells described by Andre® in S. nudus seems, to the 
author, to be due to poor preservation. 
The tentacle-like processes about the mouth may be regarded as 
branchiae physiologically, if not, also, morphologically, for a rapid 
circulation of corpuscles takes place in them ; the dorsal blood-sac is 
not merely a reservoir for blood in introversion, but must also serve as 
a conveyor of respiratory gases to the liquid of the body-cavity, and 
furnish an important aid to the thick body-wall. The position of the 
cilia on the concave oral surfaces and their arrangement along radiating 
oral grooves suggest that the branchi® also serve as means for bringing 
currents of water (and food) into the mouth. The statement that the 
cilia are on the outside surface seems to be an error due to the study of 
invaginated specimens, in which the positions of the branchial surfaces 
are apparently inverted. 
The author has been able to demonstrate the presence of a nerve- 
plexus in the walls of the digestive tract ; this is continuous with that of 
the body-wall at the anus. The digestive tract is divided into more 
numerous regions than have been hitherto recognized. The structure of 
the ciliated groove of the intestine suggests a secretory function, and at 
the same time a use as a conduit from one region to another. 
The author has already J described the structure of the reproductive 
organs, and he thinks that the arrangement which obtains may be taken 
* Amer. Natural., xxiv. (1890) pp. 646-9. 
t Studies Biol. Lob. Johns Hopkins Univ., iv. (1890) pp. 389-430 (4 pis.). 
X See this Journal, 1889, p. 518. 
