1340 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



ulur or "cervical" groove. The second is nearly confined to the broad tergal surface of the third 

 abdominal segment, while the third zone crosses the last abdominal somite and impinges on the 

 tail fin. The appendages are all colorless excepting the third pair of legs which carry the large 

 pincers. These are similarly marked with four bauds of the same bright color. As shown by the 

 colored plate two of them encircle the great claws, a third belongs to the carpus, and the fourth 

 to the uieros or fourth segment of the limb. The bases of the third and sometimes of the foiuJi 

 and fifth thoracic legs are tinged with bright blue. The ovaries often give to the dorsal surface 

 of the females a light-greenish cast. 



There is but little variation in the size and character of these markings in the same sex or m 

 different sexes, but it is most remarkable to observe how constant these colors are in individuals 

 of the species from different parts of the world. We possess two colored drawings of this spe- 

 cies* (which will be referred to again), one by Adams (5), from a living specimen taken in 

 the China Sea, and the drawing of Dana (6), who found the species on the coral reef of Earaka, 

 one of the Paumotu Islands, and at Balabac Passage, north of Borneo. Both ot these, and especially 

 the Sameraug plate, essentially agree with our Bahaman specimens, which in color seems to be 

 the more faithful copy of nature. Here the basal joints of the thoracic legs are colored bine as in 

 the Nassau form. Why should Steuopus, coming from different seas, retain the same colors and 

 markings, to a nicety of shade and pattern, while a cosmopolite like Oonodactylun chiragra (a Stouia- 

 topod) presents such wide color variations as to be as unlike as possible, so that scarcely any two 

 taken from the same place have a similar color pattern i To this question we can not at present 

 give a satisfactory answer. 



Alcohol soon removes all trace of color from the body, but the spots on the legs remain for a 

 longer time as light orange red. Both sexes are of nearly the same size, and, as already stated, 

 alike in color. 



Being thus brilliantly decorated with the American colors, our crustacean soon acquired with 

 us the name of the " Bandanna Prawn." As we see this animal swimming deliberately in the 

 water we are reminded of some strange and fantastically colored insect. It is by far the most 

 showy, and for its size the most attractive, member of that giant family, the Crustacea, which 

 have their dwelling on the reef. One day, when out upon a wading and diving expedition, a pair 

 of these prawns was discovered by turning over a plate of loose coral, and was easily captured by 

 slowly raising the slab from the water into the boat; for this species, unlike some shrimps, is quite 

 helpless when once out of its element. More frequently, however, they led us to a long chase. 



There seems to be considerable attachment between the sexes, since they are invariably found 

 in pairs, the male and female swimming side by side. On a still day they may be found clinging 

 to the mosaic of sponges and living coral, which form the reef bottom, but if disturbed they sud- 

 denly become very active, and, darting backward by sudden jerks, dive into some chink, out of 

 reach of the hand net. 



Several females both hatched and laid eggs in aquaria in the month of June, but the breeding 

 season, as inferred from the capture of locomotor larvae, probably extends throughout the spring 

 aud summer months, if not throughout the entire year. 



The eggs are very numerous. They are nearly spherical and measure one-fiftieth of an inch 

 in diameter. They were always of the same light opalescent-green color. The ova are laid at 

 night, but the process was not observed. 



Three different females hatched their broods on the afternoons of June 4, 14, aud 24, respec- 

 tively, and moulted and laid eggs during the following nights. As these animals invariably moult 

 just before laying their eggs, the latter are probably fertilized at the time they are laid. The 

 hatching of one brood lasted about 9 hours, from 2 o'clock in the afternoon until well into the fol- 

 lowing night. By 10 o'clock the same evening some of the larva; had moulted for the first time. 

 The eggs are closely felted to the abdomen, aud, as in all Decapods, they are cemented together 

 by a secretion which possibly comes from the oviducts during ovulatiou. They are fastened by 

 the same substance to the hairs which fringe the bases of the pleopods, chiefly to those of the first 

 aud second pairs. 



* Besides Milne-Ed wards figure (4), evidently made from aspecimeu in which the natural colors had been removed 

 by alcohol. (See remarks, etc., under Section iv.) 



