GOMATULA. 69 



manner of the Medusce. In swimming, the movements of the arms 

 of the Comatulce exactly resemble the alternating strokes given by the 

 Medusce to the liquid element, and have the same effect, causing the 

 animal to raise itself from the bottom, and to advance, back foremost, 

 even more rapidly than the Medicsa. Fig. 19 represents a Comatula, 

 after having delivered its stroke to the water. 



"The evidence of Pentacrimis being the young of Comatula, rests 

 upon a comparison of the individuals figured, — 20, 21, and 22, 23, — 

 the former being an advanced Pentacrimis just beginning to form 

 pinnae, and the latter the youngest Comatula ever taken by dredging. 

 In the Pentacrifius, it is to be observed that the arms are just begin- 

 ning to form pinnae towards their extremities, that they have the 

 sulphur-yellow color and dark marginal spotting observable in the 

 other, which shews, in like manner, that the upper pinnae are first 

 formed ; here, figs. 22, 23, we have about three pairs of pinnae, with 

 two intervening articulations of the arm between each, then three 

 articuli (counting from the apex downwards), and an additional pair 

 of pinnae just beginning to sprout. From this to the base of the arm 

 are five more articuli, as yet without any pinnae, the base of each arm 

 on either side presenting one long pinna appropriated to the service 

 of the mouth. On turning the animal over, the dorsal cirri are found 

 to have increased from five to nine, several of them presenting the 

 appearance of recent formation. Individuals a little older are com- 

 paratively common, in which the pinnae are complete, and from this 

 period they appear to form regularly at the apex of this arm, as this 

 goes on extending in length. These small Comatulce still retain the 

 original sulphur-yellow color towards the apices of the arms, the 

 lower part and body assuming the characteristic red of the adult 

 Comatula. From observations repeatedly made, I think it most pro- 

 bable that the Comatulae attain their full growth in one year, so as to 

 be in a condition to propagate their kind the summer following that 

 of their birth. At that time (viz., May and June,) these full grown 

 individuals have the membranous expansion inside each of the pinnae 

 considerably extended, at least as far as the fifteenth or twentieth pair ; 

 these, which are the matrices or conceptacula, at length shew them- 

 selves distended with the ova, which in July, and even earlier, make 

 their exit through a round aperture on the fascial side of each concep- 

 taculum, still, however, adhering together in a roundish cluster of 

 about a hundred each, by means of the extension and connection of 

 their umbilical cords. By what means these ova are dispersed, or how 

 they become attached to the stems and branches of corallines, remains 



