ITO MARINE PROVINCES. 



in the Gulf of Panama, while 117 extend into S. America; 635 

 species are known from the Gnlf of Panama ; of these, 266 are 

 peculiar to the district, and 163 also occur in S. America. The 

 fauna of the Panamic province in remarkably distinct from the 

 other W. American provinces, and especially the Caribbaean. 

 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 i occur on 

 both sides of the Isthmus of Darien, and this number has been 

 lately considerably increased. 



A few of the species even extend as far as W. Africa, according 

 to Dr. Carpenter ; he mentions 15, and among them the following: 

 Grepidula unguiformis, C. aculeata^ Hijyponyx antiquatus, 

 Bankivia varians, Natica maroccana^ Marginella coerulescens, 

 Nitidella guttata. Five species are common to Mazatlan and 

 the British coasts, viz., Kellia suborbicularHs, Lasea rubra^ 

 Saxicava arctica, Gytherea Dione^ Hydrobia ulvse. Woodward 

 says : " Still more remarkable is the absence of resemblance 

 between the species of Panama and those of the Indo-Pacific 

 area, there being only seven forms common to the two. Thus, 

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

 and Oliva Diiclosii, Natica maroccana, Nitidella cribraria, Hip- 

 ponyx barbatus, H. Grayanus, are scattered over the Pacific 

 ocean." The number of common species in the two Provinces 

 is now known to be very much larger. 



The river openings of this coast are bordered by mangroves, 

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

 myas, Auriculas, and Purpuras, whilst Littorinae 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. 



Galapagos 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. 



XIV. Peruvian Province. 



The coast of Peru and Chili, from Callao to Yalparaiso, affords 

 a large and characteristic assemblage of shells, of which only a 

 small part have been catalogued, although the district has been 

 well-explored, especially by d'Orbigny, Cuming and Philippi. M. 

 d'Orbigny collected 160 species, one-half of which are common 

 to Peru and Chili, whilst only one species (Siphonaria Lessonii) 

 found at Callao was also met with at Payta, a little bej^ond the 

 boundary of the region. Mr. Cuming obtained 222 species on 



