646 ALFRED C. H ADDON. 



transverse constriction of the body of the little sac draws the 

 line between the oesophagus and the stomach ; and tlie subse- 

 quent deepening of this constriction divides off the internal 

 cavity, establishing the cardiac and pyloric valves." The 

 figures which Mr. Hyatt gives are most unsatisfactory, nor 

 does he appear to have checked his observations by means of 

 sections. The minute outlines which he gives of Cristatella 

 ophidioidea (Hyatt) will equally well bear Hatschek's in- 

 terpretation. The incipient bud of Fredericella regina 

 (Leidy) (pi. vii, fig. 5, v) is made to depend from the endo- 

 cyst, but we are not informed as to the significance of the two 

 layers which he there depicts. The figure of Plumatella 

 arethusa (Hyatt) may have any interpretation. The only 

 point which is quite clear is that Hyatt believes that the 

 polypide buds are entirely derived from the endocyst of the 

 parent. 



Dumortier (18) made some interesting observations on 

 Lophopus crystallinus. He states that he has seen balls 

 of mucus floating in the general fluid of the body become 

 attached to the body-wall. '' I have said that these globules 

 appear to be of the nature of mucus, for, besides that they are 

 formed by the stomach, an eminently mucous organ, their sub- 

 stance does not permit the suj)position that they are endowed 

 with any organised tissue'^ (p. 49). "The adventitious bud 

 once disposed of, it soon establishes a focus of irritation in that 

 place, which will excite the development in the interior of its 

 mass, and a protuberance at the exterior so as to make a 

 bump." Dumortier states that the alimentary tract is de- 

 veloped from this ball of mucus, while the tentacles are 

 developed from the body-wall. The tendency of his statements 

 is towards the view of the hypoblastic origin of the digestive 

 ])ortion and an epiblastic origin of the lopho])hore, though, of 

 course, this view of the case could not present itself to him 

 (1836). 



General Concluisions. 

 In all cases of budding in the animal kingdom, so far as 1 am 



