370 Sir W. Jardine on the Ornithology of the Island of Tobago. 



sists merely of a projection inward of the substance without an 

 actual growing together or formation of a cross septum. That 

 a longitudinal septum however occurs in the upper joint, at least 

 in Crambe and Rapistrum, with the two cavities, one alone of 

 which is perfected, has already been noted. An ovule is present 

 both in the upper and the under cell, but in the upper it is erect, 

 in the lower suspended : the two funiculi arise at about the same 

 height, but on opposite sides of the cavity. Frequently the upper 

 ovule alone is developed into a seed here, while the lower is often, 

 and in the genus Crambe pretty constantly, abortive. 



However great therefore the multiformity of nature appears in 

 the silique, it may still be expected that we shall be able to trace 

 back the aberrant structures to simple typical forms when we 

 shall have discovered the transitional modifications. It would be 

 in the highest degree interesting to examine more closely many 

 cases of unusual forms of the fruit. Thus for example in Steno- 

 petalum robustum, Endl., the seeds grow upon the base of the 

 septum, in which a tripartite nerve is visible *. In Pugionum 

 cornutum, G., — a plant found, apparently, by no one but J. G. 

 Gmelin, — Gartner found an " arillus chartaceus " which com- 

 pletely inclosed the solitary seedf ; but Ledebour has ascertained, 

 from the examination of fruit in good condition in the collection 

 of A. W. Martini, who was Gnielin's companion, that the part 

 which Gartner took for an arillus was nothing else but the inner 

 layer of the pericarp, which had become so detached from the 

 outer that it was only connected by some fibres J. 



XXXVI. — HorcB Zoologicae. By Sir William Jardine, Bart., 

 F.R.S.E. & F.L.S. 



[Continued from p. 334.] 



Birds of Tobago. 



Crotophaga rugirostris, Swain. s.§ 



For our observations on this species we would refer our readers 

 to the ' Annals' of 1839, p. 160; and in a letter received from 

 Mr. Kirk since these observations were made, we have the follow- 

 ing remarks on the incubation of this curious species : — " On a 

 reperusal of your ' Horse Zoologicse ' of 1839, in regard to the 

 incubation of Crotophaga, I have now my doubts, and although 



* Enum. PI. Huegel. 4. t I>e Fruct. ii. 292. t. 142. f. 3. 



J Math, physical. Abhandl. der Miinchener Acad. d. W. iv. Bd. 3 Ab- 

 theil. 



§ Species marked n. are also found in North America ; s. in South Ame- 

 rica ; and n. s. in both. 



