230 Miscellaneous. 
Remarkable Instances of Crustacean Parasitism. 
By A. E. VeRRILL. 
In a collection of about ninety specimens of a small sea-urchin 
(Euryechinus imbecillis, Verrill) from the coast of Peru, not one 
could be found in which the anal area and surrounding parts of the 
upperside of the shell were not more or less irregularly distorted 
or imperfect. An examination of the interior showed that in each 
specimen a crab (Fabia chilensis, Dana), allied to the common 
crab of the oyster (Pinnotheres ostree), had effected a lodgment in 
the upper part of the intestine, which had thereby, been greatly dis- 
tended in the form of a membranous cyst, attached to one side of 
the shell, and extending around to the lower surface near the 
mouth. The shell is usually swollen on the side over the cyst; and 
the anal area is depressed and distorted, with a large open orifice 
passing obliquely into the cyst, out of which the crab may thrust 
its legs at pleasure, but is apparently unable, when full-grown, to 
come entirely out. All the specimens examined in the cyst were 
females, carrying eggs ; but a very small crab found clinging among 
the spines appears to be the male. The crab probably effects an 
entrance into the intestine through the anus while quite young, and, 
by its presence and growth in that position, causes the gradual dis- 
tortion of the shell and formation of the cyst. In Prof. Dana’s. 
Report on the Crustacea of the U. S. Expl. Expedition this crab is 
described as from Valparaiso, from an Echinus; but no special notice 
of its mode of occurrence and remarkable frequency appears to have 
been published*. : 
Another peculiar mode of parasitism I have observed in a sin- 
gular crustacean (Hapalocarcinus marsupialis, Stimpsont) from the 
Sandwich Islands. This creature lodges itself among the slender 
branches of a coral (Pocillipora cespitosa, Dana) and causes, pro- 
bably by its incessant motions,the branches to grow up and surround 
it on both sides by flat expansions of coral, terminating in digita- 
tions which often interlock above, leaving openings between them 
suitable for the uses of the parasite, but usually too small to allow of 
egress. Most specimens of the corals of this species sustain one or 
more, and often numerous, examples of these curious enlarged 
bulbs among the branches. The habits were unknown to Dr. 
Stimpson when he described his specimens, which had dropped 
from among recently collected corals. —Silliman’s American Journal, 
July 1867. 
On the Anatomy of Balanoglossus (Delle Chiaje). 
By A. KowaLewsky. 
Under the name of Balanoglossus, Delle Chiaje described a vermi- 
form animal of the Bay of Naples, known to the fishermen under the 
name of lingua di bue. It has since scarcely attracted any attention 
* Pinnaxodis hirtipes, Heller, recently described from Ecuador and 
found in an Echinus, is probably the same species. 
+ Proceedings Boston Soc, Nat. Hist. vi. 412. 
