18 Coelenterata. 



glyphic polyps arise sexually as well as asexually, that irregularities in the 

 number and arrangement of mesenteries may be accounted for largely by asexual 

 reproduction (usually basal fragmentation) and that the cause of variation of 

 structural types is to be sought among the causes* of variation in the number 

 of siphonoglyphs , of the correlation of siphonoglyphs and directives and the 

 like. The author also describes the Actiniid Charisea n. saxicola n., and 

 records Cribrina 1, Urticina 1, Epiactis 2 (In.). 



Parker gives details showing the migration of Sagartia IUCICB eastward 

 from New Haven and northward to Salem, the distance between these two 

 extremes having been covered probably within 10 years. 



Hazen( 1 ) cut small pieces from the base of Sagartia IUCICR. In these the 

 oesophagus regenerated from the mesogloea and endoderm, which, at the distal 

 end of the piece , form an ingrowth into the ccelenteron in the shape of an 

 inverted cup in which the mesogloea forms the middle layer and is covered 

 both inside and outside by endoderm. Later the mouth is formed by breaking 

 or perforation of the ectoderm above the cup and thus the ectoderm becomes 

 continuous with the endoderm lining the inside of the cup. The ectoderm 

 therefore takes no part in the regeneration of the stornodseum which is 

 lined by endoderm. Tentacles develop as outgrowths of the old body wall 

 (including ectoderm , mesogloea and endoderm). New mesenteries arise as 

 infoldings of the mesogloea and the endoderm which become attached to the 

 oesophagus. The orientation of the regenerating piece may or may not be the 

 same as that of the individual from which it was cut. The fixation of the 

 piece to the bottom of the dish takes place before the oesophagus regenerates. 

 The contact, in some way, stimulates the regeneration of an oesophagus at the 

 opposite end. In cases where a part of the pedal disc and enough muscular 

 tissue to allow the piece to turn over are present in the piece, the old disc 

 is retained. If however the pedal disc is absent the piece remains as it falls 

 and the point of contact marks the position of the new pedal disc. The orien- 

 tation in this case is therefore determined by gravity. 



Gravier records the capture of a new species of Cerianthus found in the 

 surface waters of the Gulf of California. Most of them contain nearly mature 

 gonads. The animal is translucent in the living state except for a faint yellow 

 pigmentation around the bluntly pointed aboral end and on the inner face of 

 the labial tentacles. The column is very contractile, when fully extended it 

 is 40-50 mm. long. There are 23-26 marginal tentacles and 24 shorter labial 

 tentacles in two alternating cycles. The two mesenteries of a couple are strikingly 

 unequal showing that they do not appear simultaneously, those on the right 

 being always in advance of those on the left. 



Menon has obtained from the Madras plankton Zoanthid larvae similar to 

 those described by Semper and subsequently in greater detail by van Beneden. 

 Of Semper's first larva (Zoanthella, van Beneden) 6 early stages and a later 

 one 8 mm. long were obtained. The latter was piriform, its mouth being at 

 the narrow anterior end. There is no aboral aperture, as described by 

 Semper. The whole ectoderm is ciliated but there is also a peculiar ventral 

 longitudinal band along 3 / 4 of the animal's length. The stomodseum is short and 

 no siphonoglyph is distinguishable. There are 12 mesenteries, 6 large (with 

 well developed filaments) and 6 small and incomplete. The highly vacuolated 

 endoderm is thick and below the level of the stomodseum nearly fills up the 

 mesenteric chambers and in the lower part of the animal the coelenteron is 

 reduced to a small irregular space and finally disappears. The youngest stage 

 is an elongate gastrula about 1 mm. long. Within the ectoderm and thin 



