530 ALFRED C. HADDON'. • 



entiates into the cavity of the hood and into the alimentary 

 tract; the generative organs arise as a pair of lateral protuher- 

 ances between the hood and the stomach ; the external orifice 

 of the hood is formed comparatively late. The muscle cells 

 and gelatinous connective tissue of the bud are derived from 

 two or three "Mesoderm" cells which make their first appear- 

 ance when there are some half dozen " Endoderm " cells, and 

 which are probably segmented off from ectoderm cells of the 

 bud. He is unable to say from which layer the foot gland is 

 derived. In this form the bud is not attached to the parent 

 by the aboral extremity of the stem but at a spot where the 

 body and the stem unite. 



It is thus quite clear that this able investigator regards the 

 whole bud as being derived from the epiblast of the parent. 



I have cut a large number of sections to elucidate the 

 question of the budding in Loxosoma. The form 1 worked at 

 was L. te thy 86, so abundant on sponges of the genus Tethya, 

 at Naples. Most of my specimens were killed with osmic acid 

 and stained in picro carmine. Unfortunately my results are not 

 so exhaustive as they might be. PL XXXVIII, fig. 25, shows 

 an epiblastic down-growth from the apex of the bud, which will 

 form the cavity of the hood ; below this is a small group of 

 cells the nature of which I am unable to state definitely ; they 

 may be mesoblastic, or they may partly or wholly be hypo- 

 blastic, for there is no reason why the closely lying hypoblast 

 cells of the stomach should not proliferate to supply its com- 

 plement towards the bud, but it must be distinctly borne in 

 mind that I have no direct evidence at present in favour of this 

 view. PI. XXXVIII, fig. 26, is a slightly later stage. At a much 

 later stage (PI. XXXVIII, fig. 27), below the hood cavity 

 lies the small circular stomach which contains a central cavity 

 and which is continued into a short blind intestine which 

 already possesses its normal curvature. I could discover no 

 connection between the stomach and the cavity of the hood. 

 Woodcut 3 would represent a diagram of such a stage. There 

 is no need to point out its parallelism with a similar stage in 

 so many other Polvzoa. The subsequent formation of an oeso- 



