80 MANUAL OF THE MOLLUSCA. 
the district, and 163 also occur in S. Ameriea. The fauna of 
the Panama province is remarkably distinct from the other W. 
American previnces, and especially the Caribbean. At one 
time it was thought that it did not possess a single species 
identical with any occurring in the West Indies or the east side 
of America. Dr. P. Carpenter, however, has shown that 35 
marine shells (15 univalves and 20 bivalves) occur on both sides 
of the Isthmus of Darien, and this number has been lately 
increased. 
A few of the species even extend as far as W. Africa accord- 
ing to Dr. Carpenter; he mentions 15, and among them the 
following :—Crepidula unguiformis, C. aculeata, Hipponyx anti- 
guatus, bankivia varians, Nautica maroccana, Marginella coerules- 
cens, Nitidella guttata, Purpura pansa. Five species are common 
to Mazatlan and the British coasts, viz., Kellia suborbicularis, 
Lasea rubra, Saxicava arctica, Cytherea Dione, Hydrobia ulve. 
Still more remarkable is the absence of resemblance between 
the faunas of Panama and those of the Indo-Pacific area, there 
being only seyen forms common to the two. ‘Thus, Cytherea 
petichialis occurs in Japan; Nassa acuta, in Australia; and 
Oliva Duclosti, Natica maroccana, Nitidella cribaria, Hipponyx 
barbatus, H. Grayanus, are scattered over the Pacific ocean. 
The river-openings of this coast are bordered by mangroves, 
amongst which are found Potamides, Arcas, Cyrenas, Potamo- 
myas, Auriculas, and Purpuras, whilst Littorine climb the trees 
and are found upen their leaves. The ordinary tide at Panama 
amounts to 16 or 20 feet, the extreme to 28 feet, so that once a 
fortnight a lower zone of beach may be examined and other 
shells collected. The beach is of fine sand, with reefs of rocks 
in the bay. 
Gallapagos Islands.—Out of 111 sea-shells collected here by 
Mr. Cuming, 43 are unknown elsewhere; 25 occur in Mazatlan, 
22 in Central America, 38 in Panama, but only 11 in South 
America. 
Littoral shells common to Panama and the Gallapagos (C. B. Adams.) 
Cyprea rubescens. Columbella nigricans. Turbinella cerata. 
Mitra tristis. Ricinula reeviana. Pleurotoma eccentrica. 
Planaxis planicostatus., Cassis coarctata. Hipponyx radiata. 
Purpura carolinensis. Oniscia tuberculosa. Fisstrella macrotrema. 
Columbella atramentaria. Conus brunneus. a9 nigro-punctata. 
“e bicanalifera. my ithe Siphonaria gigas, 
-- heemasioma. Strombus granulatus. 
