44 (JoeleiiteraTa 



sense cells than any other region, esp. in B., A. e., Ilyanthus and Cerianthus. 

 The siphonoglyph has very close-set slender sense cells, and the two ele- 

 vations which lie right and left of it, between it and the oral disc, have a 

 very rich supply of sense cells. The fibres from the sense cells in the upper 

 part of the stomodseum of B. run parallel to its axis, in the middle part the 

 fibres form a tangle and groups of bi- and multi-polar ganglion cells are present, 

 the latter arranged in narrow parallel bands separated by cell-free bands of 

 nerve fibres. In the upper part of the siphonoglyph of B. there is a definite 

 nerve tract, the chief connection between the ectodermal and endodermal ner- 

 vous systems. In B. above the junction of the oral disc, stomodaeum and 

 siphonoglyph, there is an intense red spot into which both the nerve tracts in 

 the siphonoglyph run. Judging from its position this, spot is probably connected 

 with the function of light perception. Sense cells are fewer in the endo- 

 derm but they are present in the septa, acontia and mesenterial filaments. 

 A few bipolar ganglion cells were observed in the mesenterial filaments. In 

 the Actiniae the nervous system, though primitive, is clearly centralised; the 

 centre is in the stomodaeal ectoderm, as is evidenced by the great thickness 

 of the nervous layer and the abundance of sense and ganglion cells in that 

 region. - - See also Jordan. 



Trendelenburg has investigated the gaseous metabolism in Aiptasia, Anemonin, 

 Adamsia and Asperococcus. The share of the algae in the gaseous interchange 

 was ascertained by comparing Aipt. with and without algse and also by obser- 

 vations made in light and darkness. In Anemones containing algse the amount 

 of C0 2 in the water diminishes in light, i.e., the formation of C0 2 by the 

 anemone is not sufficient to supply the needs of the algal cells. Light and 

 darkness have no influence on the oxygen-consumption of alga-free Actiniae. 

 The specific holophytic activity of the algal cells has not undergone any funda- 

 mental modification. 



Cerfontaine describes Cerianthus oligopodus from the Bay of Naples. This 

 species attains only 8 cm. in length. The tubes of those found living among 

 the rhizomes of Posidonia are grey and parchment-like, being formed of a 

 felt- work of nematocysts with a thin covering of mud ; those of specimens living 

 in sand are covered with sand grains, fragments of shells, etc. There are 

 19-21 (usually 19) marginal tentacles, i.e. a median anterior one and 9 on 

 the right and left sides, of which the 9th is smaller than the others and the 

 9th left one smaller than the 9th right. On the oral face of these tentacles 

 there are pores, the number varying with the size of the tentacle. There are 

 16-18 (generally 16) labial tentacles, all lateral in position, i.e. there is no 

 labial tentacle above the directive entocoel. C. o. is the only known species 

 in which, in the adult state, each series of tentacles is in a single cycle. Two 

 kinds of nematocysts are present in the ectoderm of the tentacles and 3 kinds 

 in that of the column wall ; they are scanty and all of one kind in the endo- 

 derm of the column wall, here also gland cells are rare but, especially in the 

 aboral region, many of the endoderm cells contain fat globules. The endo- 

 dermic nerve layer is feebly developed, probably in correlation with the weak 

 endodermal musculature. The lower end of the stomodseum is continued down- 

 wards at its sulcal edge as a gutter-like hyposnlcus (van Beneden), which is 

 especially long in this species, and ends in two pointed tongue-like hemisulci 

 (van B.) which hang freely into the coelenteron, for the directive mesenteries 

 do not extend to the aboral end of the hyposulcus. Quatroseptes are not 

 obvious in this species, probably because of the small number of mesenteries. 

 Beginning at the 3rd mesentery (not counting the directive) long fertile* 



