80 MANUAL OF THE MOLLTJSCA. 



tho district, and 163 also occur in S. America. The fauna of 

 the Panama province is remarkably distinct from the other W. 

 American provinces, and especially the Caribbsean. 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, Hijpponyx anti- 

 quatus, Bankivia varians, Natica maroccana, Marginella coerides- 

 cens, Nitidella guttata, Purpura jpansa. Pive species are common 

 to Mazatlan and the British coasts, viz., Kellia suhorhicularis, 

 Lasea rubra, Saxicava arctica, Cytherea Dione, Hydrobia idvcB. 

 Still more remarkable is the absence of resemblance between 

 the faunas of Panama and those of the Indo-Pacific area, there 

 being only seven forms common to the two. Thus, Cytherea 

 petichialis occurs in Japan; Nassa acuta, in Australia; and 

 Oliva Dudosii, Natica maroccana, Nitidella criharia, Hipponyx 

 barhatus, H. Grayanus, are scattered over the Pacific ocean. 



The river-openings of this coast are bordered by mangroves, 

 amongst which are found Fotamides, Areas, Cyrenas, Potamo- 

 myas. Auriculas, and Purpuras, whilst Littorince climb the trees 

 and are found upon 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. 



Oallapagos Islands. — Out of 111 sea-shells collected hereby 

 Mr. Cuming, 43 are unknown elsewhere; 25 occur in Mazatlan, 

 22 in Central America, 38 in Panama, but only 11 in South 

 America. 



LiMorcd shells common to Panama and the Gallapagos (C. B. Adams.] 



Cyprsea rubescens. ColiunLella nigricans. Turbinella cerata. 



Mitra tristis. Eicinula reeviana. Pleurotoma eccentrica. 



Planaxis planicostatus. Cassis coarctata. Hipponyx radiata. 



Pmpura carolinensis. Oniscia tuberculosa. Rssiu-ella macrotrema. 



Columbella atramentaria. Conus brunneus. „ nigro-punctata. 



„ bicanalifera. „ bux. Siphonaria gigas. 



„ heemastoma. Strombus granulatus. 



