170 



SCIENCE. 



[N. S. Vol. XI. No. 266. 



literation of the spiracle, and the fusion 

 of the palato-quadrate with the cranium. 

 Dermal margin of the hyoidean arch de- 

 velops early and partly encloses the hinder 

 gill slits. Long external gill-filaments (aris- 

 ing as in shark from the posterior margin 

 of the gill bar) are now present. Tail be- 

 comes exceedingly long and attenuated. 

 A highly specialized character is the mode 

 of absorption of yolk material during late 

 embryonic stages. The extra-embryonic 

 blastoderm surrounds a lobe of the yolk : 

 the latter comes to be reduced to independ- 

 ent lobes, and later to a milky fluid which 

 is doubtless appropriated by the embryo by 

 means of its external gills. These now 

 present greatly dilated blood nodes, red in 

 color. The late embryo lies in an opaque 

 nutritive fluid, its relatively small and 

 irregularly shaped yolk sac represents the 

 small lobe early separated from the yolk. 



On the occurrence of ampMoxus at Bermuda : 

 C. L. Bristol and F. W. Carpenter. 

 Amphioxus was first found in Bermuda 

 by Professor G. Brown Goode in 1877, but 

 no specimens have ever been studied from 

 the lot then collected. In the season of 

 1897, the Second New York "University Ex- 

 pedition dredged for them unsuccessfully, 

 but in the next season specimens were se- 

 cured by Professor Verrill in April, and 

 again in June by the Third New York 

 University Expedition at the locality de- 

 scribed by Goode at the Flatts Bridge. In 

 addition to this locality, the New York 

 University party found them near Trunk 

 Island in Harrington Sound. Specimens 

 were sent to Professor E. A. Andrews, who 

 reports that they promise to prove Bran- 

 chiostoma caribaeum. 



Budding in Cassiopea: E. P. Bigelow. 



In the course of an extended study of the 

 development of Cassiopea xaymacana, a rhi- 

 zoatomatous medusa obtained in Jamaica, 

 the author found it possible to draw an in- 



teresting comparison between the process of 

 budding and strobilization. The buds are 

 formed one at a time on the lower part of 

 the calyx of the scyphistoma. The bud is 

 an evagination of the body wall consisting 

 of three layers — ectoderm, mesogloea, and 

 endoderm ; and in the mesogloea are embed- 

 ded four longitudinal muscles which are 

 formed by outgrowths from the adjacent 

 longitudinal muscles of the present. 



In the formation of the strobila, the 

 greater part of the scyphistoma is con- 

 verted into the medusa disc, while the 

 basal polyp is a comparatively small and 

 simple appendage serving mainly for sup- 

 port. This, like the bud, consiBts of a 

 simple sack with a wall of three layers — 

 ectoderm, mesogloea and endoderm, and in 

 the mesoglcea there are four longitudinal 

 muscles. Just before the separation of the 

 medusa the basal polyp forms eight ten- 

 tacles, and a ridge of ectoderm grows out in 

 a circle surrouadiug the isthmus. When 

 medusa is set free, this ridge enlarges to 

 form a proboscis, more tentacles are devel- 

 oped, and very soon the basal polyp can- 

 not be distinguished from an ordinary scy- 

 phistoma developed from a bud. 



Before the bud is set free its proximal 

 and distal ends become differentiated struc- 

 turally, so that it is easy to distinguish 

 them. Soon after becoming free the planula- 

 like bud becomes attached to some solid 

 support by its distal end, and the mouth is 

 formed at the proximal end and becomes 

 surrounded with a crown of tentacles, the 

 orientation is just the opposite of wiiat one 

 would expect and corresponds with what 

 Claus and Goette found to occur in Coty- 

 lorhiza. 



So the bud and the basal polyp not only 

 correspond in general structure, but in both 

 it is the proximal end that forms the mouth 

 and the distal end the foot. Their orien- 

 tation is the same, and while attached to the 

 calyx, their central axes meet as an acute 



