The Actiniae of the Plate Collectioii. 257 



sectioned several tentacles from the same and from other individiials, 

 but in no case could I find any signs of its presence. 



Transverse sections of the tentacles showed the existence of 

 long'itndinal ridges of mesog'loea which give rise to the fluted 

 appearance. The longitudinal muscnlature of the tentacles and the 

 corresponding- radial muscnlature of the disc are ectodermal and 

 fairly strong, the mesogloeal lamellae which support it in the 

 tentacles being higher and more numerous over the ridges than in 

 the intervals between these. In some preparations the mesogloea 

 had a reticular structure suggesting a mesogloeal muscnlature. but 

 no traces of muscle fibres could be found in the meshes of the 

 reticulnm, nor was the reticulum of general occurrence throughout 

 in any one tentacle. 



Two well developed siphonoglyphs are readily distinguishable 

 in sections through the stomatodaeum. the slight development of 

 their corresponding gonidial grooves being due to their having been 

 flattened out by the evagination which the stomatodaeum had 

 nndergone in many of the specimens. The mesenteries were arranged 

 in four cycles, one individual, that in which the tentacles were 

 counted, showing an incomplete development of a fifth and some 

 irregularities in the fourth. Twelve pairs of mesenteries weie 

 perfect, six of these, however, separating from the stomatodaeum 

 sooner than the others, which included the two pairs of directives. 

 The longitudinal muscles Avere moderately developed; at the lower 

 edge of the stomatodaeum they occupy the greater portion of the 

 non-gonophoric part of the niesen tery and increase gradually in 

 height from without inwards, ending abruptly at the inner edge. 

 The parieto-basilars are feeble, not forming a fold and the basilar 

 muscles are also weak, resembling those which CarlCtKen has figured 

 for B. Jongicornis. 



A few words may be added concerning the sphincter of the 

 Bolocerids. There are within the limits of this family sphincters of 

 all gradations from ''absent" to "strong endodermal circumscribed". 

 but in the majority of the species they are endodermal and diffuse. 

 Even in these, however, considerable variety has been found; thus 

 in B. longicornis Caelgken, B. occidua Mc M., B. brevicornis Mc ^\. 

 and in my preparations of B. multicornis Veekill the sphincter is 

 typically diffuse, while in B. l:erguelensis Studer, B. pannosa Mc 31., 

 B. multipora (Hertwig), B. tuediae Verrill and in Carlgren's 

 figures of B. multicornis there is at the upper edge of the muscle 



