mVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 649 



refractive, fusiform, and nearly tlircc times as long as the coll itself. 

 Glandular cells not essentially diftering from those above described 

 are also met with. 



Mesembryenthal Filaments. — ^The surface of the stomach is not 

 smooth, but covered with longitudinal elevations, very rich in 

 glandular cells, each of which corresponds to the place where a 

 septum unites with the stomach. At the extremity of the stomach 

 the protuberances form the free edges of the mesembryenthal septa ; 

 there is therefore an unbroken continuity of these longitudinal pro- 

 tuberances at the surface of the stomach with the mesembryenthal 

 filaments, and this fact explains the complete unity in the structure 

 of these two organs and shows that they can only act as an organ of 

 digestion. The filaments are solid, and have no interior cavity. 

 There is no canal passing through the septa and uniting the chambers 

 formed by them. 



Antipatharia of the ' Blake ' Expedition.* — Twelve species of 

 this interesting group taken in the Caribbean Sea (1878-79) are 

 described by L. F. Pourtalcs. In determining the species an attempt 

 has been made to use the diftcrences in the shaj)e of the polyps, as 

 well as the disposition and form of the sjjines, to draw characters for 

 a much-needed revision of their classification. It would seem as if 

 there were at least two difterent types of spines ; the triangular com- 

 pressed and the more cylindrical. These latter are generally more 

 densely set, even assuming sometimes a brush-like appearance, as in 

 Antipathes humilis, a new and wonderfully spinous species, figured but 

 not described. These cylindrical spines are also unequal on the two 

 sides of the pinnules, being longer on the side occupied by the polyps, 

 with a few very mucli longer around the polyi^s. In one species, how- 

 ever, A. Dcshonni, the spines are in regular verticils. There would appear 

 to be a connection between the shape of the polyps and the shape and 

 dis2>osition of the spines. Those si)ecies with triangular spines have 

 polyps with longer tentacles than those with cylindrical spines, and 

 the tentacles have a greater tendency to become regular in shape. In 

 many sjiecies the tentacles are simply contracted ; in a very few they 

 were found retracted, as figured by Lacaze-Dutliiers ; and in somo 

 they arc probably not retractile at all. 



Eight out of the twelve named are cither desci'ibed or figured as 

 new species. A. spiralis is a very interesting si)ccies, formerly 

 referred to A. Dcshuiini D. and M. The polyps are alternately largo 

 and small, with very large digitiform tentacles much longer than have 

 been figured of any Antipdlhes before. In the spaces between 

 successive polyps the ccenosarc shows transverse canals, and those ou 

 the back part of the branch are more transparent than the rest. 



American Siphonophora.f — Mr. J. W. Fewkcs gives a sketch of 

 the developuuiit of the tentacular knob of Phijsophora hifdrcslafica. 

 Tho growth of this knob is here more complicated tlian in any 



» 'IJull. 'Slws. Comp. Zof.l. Camb.,' vi. (1880) p. US. Sec 'Nature,' xxii. 

 (1880) p. IKl 



t Il'i.l.. p. 127. Stc 'Nuluro.' xxii. (1880) p. 11:5. 



