PAIRING, COURTSHIP, AND PARENTAL CARE 307 



pleasure, trying to persuade her to enter through the circular 

 aperture in the side, aiding her entrance by poking her 

 vigorously with his snout, or, if she be slow, even using his 

 spines. She proceeds to deposit two or three eggs within, finally 

 boring through the wall of the nest on the side opposite to the 

 entrance and swimming away. While she is in the nest the 

 male swims round and round in great excitement, butting and 

 rubbing his snout against the fabric. He then enters, deposits 

 his milt on the eggs and departs through the back door. Next 

 day he seeks out another female, and repeats the whole process 

 with her, and so on, v/ith one after another, until sufficient eggs 

 have been deposited. The male now mounts guard over the 

 entrance, defending his charge with vigour against all comers 

 for nearly a month, furiously attacking any other Stickleback 

 that attempts to approach the nest. From time to time he 

 repairs any damage to the walls, and Mr. Frank Buckland 

 describes how in a nest which he watched the little sentry 

 kept "constant watch over the nest, every now and then shaking 

 up the materials and dragging out the eggs, and then pushing 

 them into their receptacles again, and tucking them up with 

 his snout, arranging the whole to his mind, and again and 

 again adjusting it till he was satisfied." The two doorways 

 allow a constant current of fresh cool water to bathe the 

 eggs within the nest, but he may assist this process by placing 

 himself at the entrance and vibrating his pectoral fins. Even 

 when the young hatch out his task is by no means done, but no 

 the contrary his vigilance is increased and his duties multiplied. 

 He pulls down the upper part of the nest, leaving the foundations 

 as a kind of cradle for the fry, which he continues to guard as 

 before, preventing any attempts on their part to leave the nest 

 by seizing the truants in his mouth and returning them to their 

 quarters. As soon as they can swim strongly, however, he 

 gradually relaxes his attentions, although still keeping a watchful 

 eye on them as they swim about in the water, until finally 

 they are left to fend for themselves. The Fifteen-spined 

 Stickleback (Spinachia), an exclusively marine form, builds an 

 elaborate nest from a suitable branch of seaweed, binding the 

 fronds of weed with the sticky secretion from the kidneys. 

 The threads are passed round and round the fronds until they 

 are finally bound together into a roughly pear-shaped structure 

 of about the size of a man's clenched fist. 



Many of the Labyrinthic-fishes [Anabantidae) make a most 

 unusual type of nest, the male blowing bubbles of air and 



