2 
Diego, by Mr. Henry Hemphill, and my pleasure was still greater when I 
found, upon comparison with the specimens already in our museum, and 
with the writings of Stimpson and 8. I. Smith, that this donation enriched 
us with at least 20 species new to science. 
Up to this present time no species of Crustacea from Panama, and only 
one or two from the coast intervening between that point and San Diego, 
have reached this Academy, and the amount of zoélogical riches yet remain- 
ing to be harvested in this quarter, may be guessed at from the fact that these 
twenty species were collected incidentally, as it were, the Crustacea not being 
the chosen field of the collector. 
It is with some diffidence that I refer some of these species to their genera, 
simply because we have not in our collection specimens of many well known 
genera, nor have we in our defective library any figures or description of the 
already known species included in them. 
To make clear to others the difficulty under which I and any other person 
who attempts to do a little original work in connection with this institution, 
are compelled to labor, I have but to state that two of the species described 
in this paper belong to a group of crabs, the macropodidae (distinguished by 
the great length and thinness of their legs), no species of which has before 
been known on this coast, but of which the typical forms are described and 
figured in such standard works as those of Milne Edwards, and Bell’s British 
Stalk-eyed Crustacea, neither of which works are to be found in our library. 
I have, therefore, in determining the genera, been compelled to be guided 
alone by the generic descriptions given by Dana in his Crustacea of U. 8. 
Exploring Expedition, the only comprehensive work accessible to me, and 
that is lent to the Academy. 
Before proceeding to the technical description of the new species, I wish to 
draw the attention of all members of the Academy at all interested in zodlogy, 
to a few peculiarities in our list of native Crustacea as it stands at present. 
Two species of Macropodidae, as I have just said, are all that are yet 
known. The crabs of this tribe are sluggish in their habits and are usually 
found among sea weed, sponges and zodphytes, at depths below those left 
bare at the lowest low tide, and are thus only obtained by dredging, unless 
cast ashore in some storm along with the sea weed among which they live. 
It is, therefore, almost a certainty that a properly organized search would 
disclose several other species, even in this immediate neighborhood. 
Of the Xanthidae, a sub-family near the true cancer, not a single species has 
been described by Stimpson or Dana, and it is singular that among the newly 
found San Diego species this tribe predominates. 
Only two species of the swimming crabs (Portunidae), have yet been found 
in California, one of these (Lupa bellicosa), has been described by Stimpson, 
and the other is new. 
The parasitic Crustacea of various orders have not yet been collected with 
any thoroughness, but I may here mention that several, (so far as I am 
aware) undecribed forms have recently been added to our collection, and 
that I hope, during the course of this year, to be able to prepare another 
paper upon them and upon other undescribed species not included in the 
present paper. 
