12 Mr. J. Miers on the Menispermaceae. 



commissures, upon which very slight swellings, representing 

 the future ganglia, may barely be perceived. 



In the larvae of the Lobster, on the contrary, and in those of 

 the Zo'ea-form in which the abdomen is well developed, we see 

 the double ganglionic chain from the very first, formed, as it 

 will be subsequently, of six pairs of ganglia, already of consi- 

 derable size, and bound together by the longitudinal commis- 

 sure. Here, as in the thoracic portion of the central system, two 

 pairs of nerves issue from each of the ganglia and from the 

 cords by which they are connected. 



IV. — (hi the Menispermaceae. 

 By John Miers, F.R.S., F.L.S. &c. 



[Continued from vol. xvii. p. 270.] 



29. Stephania. 



This genus, proposed by Loureiro in 1793 for two plants of 

 Chinese origin, was for a long time wholly neglected ; at length 

 it was acknowledged by botanists, and so far extended by some 

 as to embrace Blume's genus Clypea ; others, on the contrary, 

 under vague notions of its real characters, gave the preference 

 to Clypea, and included in it all the species of Stephania. The 

 authors of the ' Flora Indica ' and of the ' Genera Plantarura ' 

 have united the two genera, on the authority of Prof. A. Gray, 

 who placed little dependence on the constancy of their relative 

 distinctions as I had defined them : his doubts arose from the 

 examination of a plant considered by him to be identical with 

 Cocculm Forsteri, DC., which had been referred to Stephania ; 

 it appeared to him that its floral parts were sometimes 3-merous, 

 at other times 4-merous, in the same specimen — an inference 

 upon which I offered some remarks in speaking of Clypea (vol.xvii. 

 p. 268). In all the instances examined by me, which are ex- 

 tremely numerous, I have found, without exception, that the 

 floral parts in the two genera are constantly different in number. 

 Stephania in its (^ flower has six sepals in two series, three 

 smaller petals, and a 6-celled anther; while Clypea, as I have 

 shown, has eight sepals in two series, four petals, and an 8- 

 celled anther. In Stephania the $ flower has three sepals, three 

 petals, and a putamen with a remarkable perforation in the 

 middle of its disciform condyle ; while Clypea has four sepals, 

 two petals, and a putamen with an imperforated condyle, as in 

 Ileocarpus and Cissampelos. Many good characters also separate 

 this genus from Homocnemia and Ileocarpus : although the latter 

 has a similar number of sepals and petals, the imperforation of 

 its condyle renders it distinct; the former has four sepals and 



