NATURAL SCIENCES OF PHILADELPHIA. 55 



ish-white. We have observed this species to have a wider rans^e, to congre- 

 gate iu larger numbers and exhibit more activity than others of lh3 Dolphin 

 family. They are seen in numbers varying from a dozen up to many hun- 

 dreds, tumbling over the surface of the sea, or making arching leaps, plung- 

 ing again on the same curve, or darting high and falling diagonally sidewise 

 upon the water with a spiteful splash. 



When a brisk breeze is blowing they frequently play about the bow of a 

 ship going at her utmost speed, the animal cutting across the bow and shoot- 

 ing ahead, or circling around the vessel, apparently sporting at CHse. 



They are found in every ocean, and are often seen in considerable numbers 

 about the large bays and lagoons along this coast, that have no fresh water 

 running into them. They abound more along coasts where small fish are 

 found than in mid ocean, as they prey upon the smaller finny tribes, and to 

 obtain them shoot swiftly through the water, seizing the object of pursuit 

 with the slightest effort. Occasionally a large school of them will get into a 

 shoal of fish, frightening them so much that they will dart around in all 

 directions, taking no regular course to escape their pursuers, and finally get 

 so bewildered as to lose nearly all control over their movements. At such 

 times the Porpoise is manifestly the "sea swine," filling itself to repletion. 



In perfectly calm weather they are sometimes seen huddled togetiier on the 

 glaring surface, their heads slightly raised, or reclining a little on their sides, 

 as if resting from their constant activity ; but such instances are not frequent. 

 Generally they are seen in large numbers rushing over and through the undu- 

 lating sea, exhibiting their active habits and propensity to roam over an 

 unlimited extent of ocean. 



RIGHT-WHALE PORPOISE. 



The Right-whale Porpoise in form and habit is nearly the same as the Fin- 

 back, except it has no fin on its back, and is rather more slender in proportion 

 to its length. They are not seen in as large numbers, and are seldom found in 

 shallow bays and lagoons. We have met with animals of this genus from 

 about Cape Horn as far north as Behring Sea, showing plainly that their feed- 

 ing grounds embrace the whole coasts of North and South America on the Pa- 

 cific side, if no more. 



THE COW-FISH. 



A species of Porpoise, larger than the Finback or Right-whale kind, is 

 known under the name of Cow-fish. It is longer also in proportion to its 

 greatest girth, but its head is not as long. Its teeth are larger, less in number, 

 and it differs in its color, being of a dull black, lightened a little on the belly. 

 This description is based upon two momentary observations — the first at St. 

 Bartolme Bay, in 1853, and the other in Ballena's Lagoon, in 1859. In its 

 habits, likewise, as observed on the coasts of California, Mexico and Peru, it 

 shows a striking difference. They are often remarked upon by whalemen as a 

 "mongrel breed," of doubtful character, often seen in company with Black- 

 fish, sometimes with Porpoises, and occasionally with Humpbacks, when the 

 latter are found in large numbers on an abundant feeding ground. They are 

 met with likewise in the lagoons along the coast, sometimes singly, or in pairs 

 or fives and sixes — rarely a larger number together — straggling about in a va- 

 grant manner through the winding estuaries, subsisting on the fish that abound 

 in them. At times they are seen moving lazily along under the shade of the 

 mangroves that fringe the shores in many places, at other times lying about in 

 listless attitudes among the plentiful supplies of food surrounding them, con- 

 sisting of many varieties of the finny herds that swarm in those waters. 



THE KILLER. 

 Oeca rectipinna Cope. 

 The Killer is a peculiar species of Cetacean, that is found wherever the Ba- 



1869.] 



