488 Mr. E. E. Prince on the Nest and 



occur most frequently amongst sea-weeds fringing tidal pools, 

 and of such marginal weeds tliey are constructed. Prof. 

 Mobius states * that the nests vary from 2 to 3 inches 

 (5 to 8 centims.) in diameter ; but these dimensions are often 

 exceeded, the size being very variable and depending on (1) the 

 character of the materials employed, and (2) the number of 

 fishes depositing their ova in a particular nest. It is remark- 

 able that the eggs of more than one female may be deposited 

 in a single nest. This actually took place in the tanks of the 

 laboratory — a female taking possession of an old nest, which 

 contained advanced ova, and upon completing oviposition in 

 the lower part of the nest, the male immediately surrounded 

 that portion with binding threads. That the number of ova in 

 one nest is often greater than a single female produces has 

 been noticed by many observers ; and Couch, struck by their 

 disproportionate bulk, said that it was " only to be explained 

 by the well-known fact that the ova of fishes generally obtain 

 an increase of bulk by the absorption of water after ex- 

 clusion "f; but the enlargement of non-pelagic eggs with 

 dense capsules is not sufficient to account for the phenomenon 

 in question, and the explanation is to be found in the plurality 

 of females resorting to a particular nest. The male fish, 

 which is the nest- builder, often selects a growing mass of 

 Fucus-fronds, projecting 8 or 10 inches from the rock, and 

 having a diameter of 5 or 6 inches in the widest part (PI. XIV. 

 fig. 5). A bunch of more minute Algse, e. g. Gerammm, 

 Co7'aUina, &c., may be chosen, and the nest assumes a less 

 cylindrical and more spherical form, measuring from 3 to 5 

 inches in diameter. In the former case little labour is required 

 in building, the male merely binding the fronds by delicate 

 circumscribing threads, which pass round transversely to the 

 long axis of the mass (PI. XIV. fig. 5, a, a). In the latter 

 case, in which softer and less coai'se materials are used, much 

 labour is involved, the growing tuft forming merely the basis 

 upon which the gathered fragments of AlgaB, Ulva, Corallina 

 officinalis^ Hydrozoa, &c. are woven ; this heterogeneous collec- 

 tion of dead fragments being intermingled with the fronds of 

 the living plant and secured by tenacious threads, so that a 

 somewhat compact mass is formed (PI. XIV. fig. 5). The 

 nest is pendulous and, being firmly anchored, is swayed about 

 by the movements of the tide. So compactly are the mate- 

 rials interwoven that it is often difficult to tear them asunder, 

 though they are always so disposed as to leave interspaces 

 which are enlarged into more capacious chambers by the 



* Vide Note in Aug. part (1885) of this Joiu-nal, p. 153. 

 t Couch, Hist, of Fishes of Brit. Islands, vol. iii. p. 182, 



