i 9 4i CATALOGUE OF FISHES OF TORTUGAS ^5 



adhesive filaments to corals, generally on an eroded overshadowed surface, 

 though once two nests were found on the upper surface of bare rock lying on the 

 bottom. The ' nest" may cover an area about a foot in diameter. 



The nests are guarded by a parent fish. The three captured while performing 

 this duty were all males. These fish evidently have no easy task, as they were 

 kept busy during the observations, dashing wildly, driving away small (young) 

 Halichoeres bivittatus, Thalassoma bijasciatum, Pomacentrm sp., Malacoctenus 

 sp., and Rupiscartes atlanticus. One fish may guard three or more different 

 clutches of eggs during a single season. This was learned through the observation 

 of a fish with a malformed profile, that appeared on duty among the same coral 

 heads two seasons in succession. One season, when it was watched rather closely, 

 it guarded at least three different clutches of eggs in the same place between June 

 27 and July 24. 



Only once two fish were seen together at one nest, the one much smaller than 

 the other. As the larger fish, 150 mm. or so in length, remained to guard the eggs, 

 and the smaller one was seen there only this one time, when it was more than 

 tolerated, it is assumed that it was a female. It was not actually seen in the process 

 of depositing eggs, but it seemed to be engaged in cleaning the nest, or the sur- 

 face on which eggs were to be deposited. 



The eggs are longer than broad, and a little larger at one end than the other, 

 but depart little from an ellipsoid form. The greater axis of the egg is approxi- 

 mately 1 mm., and the cross axis at mid-length of the egg is about half that 

 length. The adhesive threads spring from the larger end of the egg. Its color is 

 rose red. In the nest under water the eggs were of a muddy amethyst color. 

 Under the microscope the yolk is a vivid purple. Each egg contained one large 

 and a varied number of smaller oil globules of different sizes. 



The length of the period of incubation was not definitely determined. Eggs 

 brought to the laboratory died before hatching. Eggs in an advanced cell division 

 stage when first observed in nature had hatched 5 days later. The incubation 

 period, then, apparently extends over 5 or possibly 6 days. 



Atlantic coast of tropical America northward to Florida, sometimes straying 

 as far north as Cape Cod. S. F. H. 



Abudefduf taurus (Miiller and Troschel) 



(Plate 24, fig. 2) 



Glyphisodon taurus Miiller and Troschel, in Schomburgk, Hist. Barbados, 1848, p. 674 — 



Barbados. 

 Glyphisodon rudis Poey, Memorias, vol. 2, i860, p. 191 — Havana. 



Rare at Tortugas, a dozen or two individuals of all ages apparently represent- 

 ing it during a large part of the year. Its distribution, however, is so precisely 

 correlated with a particular sort of habitat that few species may be more surely 

 discovered at will and studied at leisure. It was seen only at the shore, and then 

 under natural conditions only where blocks or sheets of beach rock on the east or 

 west side of Loggerhead Key afford shelter. About Garden Key a few were 

 usually found where tracks for hauling out boats or where horizontal pipes not 



