a 
3 
: 
4 
ee OS ee ee ge 
Ree Ps Sa ie eee 
shinee Sane a ses Sac eae eae e ete oy ati ee a e 
Saget eats eee aa et 
ceeds that of 
1876.] Zovlogy: 429 
The Growth of Maize begun in an Atmosphere free from Carbonic 
Acid. Schnetzler, Action of Sulphide of Carbon on the Insects infesting 
Herbaria. No. 16. A. Trécul, On the Capillary Theory, illustrated by 
Amaryllidacez. 
Flora, No. 10. Georg Winter, On some Ustilaginee. Kraus, On the 
Formation of Hairs on Potato Sprouts. Geheeb, Mosses from the 
Mountains near the Rhone. De Krempelhuber, Brazilian Lichens. 
of the Waxy Deposit on Cuticle. Brefeld, On the Culture of certain 
Fungi. No. 16. Holle, On the Growth of Roots of Angiospermous 
Plants, with Special Reference to the Root-Cap. No. 17. Sadebeck, On 
the Relation of Pythium Equiseti to the Potato Fungus. No. 18. Vel- 
ten, On Electricity in Plants. 
ZOOLOGY. 
_ ANOTHER CASE OF ANIMAL COMMENSALISM. — An interesting in- 
stance of animal commensalism came to my notice recently, during the 
cruise of the United States ship Portsmouth among the islands of the 
Pacific Ocean. I found in the cloacal dilatation of the alimentary canal 
of a holothurian a crab belonging to a class higher in the scale of classi- 
o than any that has yet been discovered possessing parasitical 
adits. 
tis the first instance to my knowledge where a crustacean of the 
84 type Cancroidez has been found living as a “ free messmate ” within 
the body of another animal. It belongs to the family Portunide, or 
swimming crabs; and it is one of those aberrant forms, or connecting 
links, uniting the natatorial and the gressorial species. 
It represents not only a new species, but a new genus; and Dana un- 
consciously possessed the type of the genus in a little individual which 
he found on the coral reef at Ovolan, Feejee Islands. He modified an 
already existing genus (Lissocarcinus White) in order that it might re- 
ceive his species ; yet, in spite ‘of his modification there exists almost as 
Wide a difference between the two as between two common genera of our 
Own coast, Oarcinus and Platyonichus, which are related in the same 
in the description of his species (Lissocarcinus polyboides), 
is a powerful swimmer, with the tarsi of the posterior pair 
y expanded ; while in Dana’s species the tarsi are flattened 
d in about the same proportion as in Carcinus, a littoral ge- 
he lateral expansion of the tarsus of the last pair scarcely ex- 
the three preceding pairs. 
pecies was a male; while the one which I found was a fe- 
It is well known that among crustaceans it is generally the fe- 
of feet broad! 
and expande 
nus, where't 
as s 
male, 
