192 PROCEEDINGS OF THE ACADEMY OF [1895. 



but their range does Dot extend very far northward. Accordingly, 

 arctic circumpolar species are not known, the northern litoral species 

 being restricted to comparatively narrow districts, each to one side of 

 the great oceans. Only one species, P. norvegicus, in the northern 

 Atlantic, is found on both the European and American shores. 

 Eight species are found in the European seas: P. echimäatus, 

 spinosus, pattersoni, sculptus, bispinosus, trispinosus, fasciatus, 

 neglectus; one on the east coast of United States : P. brevirostris. As 

 the cooler waters of the western African coast allow a more south- 

 ward extension, a mediterranean species, P. cataphractns, ranges 

 southward to the Senegambia. In the Pacific northern species 

 are not known, but two having a more southward range: P. 

 bidentatus in Japan, P. earinicauda in China. The presence of the 

 latter in the tropics is due, I believe, to a more recent immigration. 

 Of the northern litoral species some show a very large bathymetri- 

 cal range, descending to considerable depths, especially P. echinu- 

 latus, brevirostris to 150 fathoms, P. norvegicus to 500 fathoms. The 

 next to the latter species, as regards the depth inhabited, are P. 

 bengalehsis, andamanensis, juneeus, being found in the tropical seas 

 of India and Indo-Malaysia in depths of about 100 to 300 fathoms, 

 and, farther, five Species are true deep sea animals. One of these, 

 P. profundus, is only found near Sydney in 2, 600 fathoms, another, 

 P. occidentalis, off the west coast of Central America in 900-2, 200 

 fathoms. The three others show the characteristic wide range of the 

 true abyssal animals, Pont, gracilis being found in the Atlantic and 

 Indian oceans from 200 to 700 fathoms, P. abyssi in the North 

 Atlantic and Indian oceans from 1700 to 2,200 fathoms, and P. 

 'ehaUengeri in the Atlantic and Pacific oceans from 1,100 to 2,700 

 fathoms. Lastly, two litoral species are known from the cooler seas 

 of the southern hemisphere: P. australis from New Zealand, and P. 

 intermedins from Southern Australia, 



The horizontal and vertical range of Pontophilus may be sum- 

 marized as follows: The main distribution of the genus is in the 

 litoral of the northern hemisphere, especially in the temperate seas, 

 a circumpolar rangeof none of the species is proven ; a few litoral 

 species extend more southward. A great number of species have 

 a tendency to descend into deeper water, and, accordingly, some 

 species are found in the deeper water even of the tropics, and have 

 occupied a large area of the deep sea. In the cooler parts of the 



