The bullhead does not actually build a nest, like the stickleback, but makes an egg-house, on the bottom of some slowly-running stream. The male usually selects a hollow under a boulder, or a space betwixt two stones, and shoves out the lesser pebbles and gravel, to form a pit. This accomplished, several females are in turn induced to deposit their roe, having done which they are driven off by the male, who supplies the milt, then shovels the sand and pebbles, with his huge horny head, over the treasure, until it is completely covered: more females, more eggs and milt, more shovelling, until the affair is completed to the bullhead papa’s satisfaction. Now stand clear all thievish prowlers! Let anything of reasonable size venture near—then head down, and plying all his propellers to their utmost power, he charges at them, driving his horns in to the very hilt; free again, seizes hold with his mouth—thus biting and stabbing, until he kills or routs his foe. I am not able to say exactly how long the eggs are incubating, but, as nearly as I could observe them (in the Sumass and Chilukweyuk streams), in about eight weeks the young escape from the egg-house. The females were invariably driven away, with the same ferocity as other unwelcome guests, from the depositing the spawn to the exit of the infant fish: then old and young disappear into deeper water, and are seldom seen again. During the winter, I constantly obtained the bullheads from out the seine-nets used in Esquimalt Harbour to procure fish for the supply of Victoria market. Rejected by the fishermen, the Indians greedily gathered up the despised fishes, broiled them over the lodge-fire empaled on a slender twig, then feasted right-royally on the grilled remains of the spiny martyrs. The genus _Centridermichthys_ is characterised as follows:—Head more or less depressed, rounded anteriorly; head and body covered with soft and scaleless skin, more or less studded with prickles or granulations; teeth in the jaws, on the vomer and palatine bones. _Centridermichthys asper_ (_Coltus asper_, Rich. F. B. A. ‘Fishes,’ p. 295), the Prickly-skinned Bullhead.—_Sp. Ch._: Gill-openings separated beneath, by an isthmus; three opercular spines; crown with very small warts, back of the body with very minute spines; colour light yellowish brown, thickly dotted with spots nearly black. The length of the adult fish is seldom over three-and-a-half inches.