112 MR. MIERS ON ANOMALOUS DEVELOPMENTS OF THE RAPHE iN SEEDS. 



Fig. 35. The seed detached, showing the annular raphe : — a. commencement of the raphe at the hilum ; 



b. termination of the raphe. 

 Fig. 36. The same seen edgeways. 



Fig. 37. The raphe detached : — a. its commencement at the hilum ; b. its termination at the chalaza. 

 Fig. 38. Section of albumen, showing a minute embryo near its base: — c. relative position of embryo 



with the commencement a, and the termination b, of the raphe. 

 Fig. 39. Base of albumen with embryo greatly magnified, the same letters referring to the same parts. 

 Fig. 40. An anatropal ovule of Cucumis Anguria near the period of its fertilization; after Mirbel. 

 Fig. 41. The same seen just after impregnation; also after Mirbel: — a. the primine ; b. secundine ; 



c. tercine or nucleus ; d. quartine or embryo-sac suspended at the micropyle or mouth of the 

 primine and secundine ; e. base of embryo-sac broken away from its attachment to the chalazal 

 point of the tercine ; /. the nascent embryo hung in the mouth of the micropyle by its suspen- 

 sor ; g. the gangylode or point of union of primine, secundine and tercine, and the future cha- 

 laza ; h. two layers of solid cellular tissue forming a distinct coating secreted and deposited over 

 the primine ; i. the raphe originating in the funicular cord, and terminating at g, the gangylode 

 or chalazal point ; k. a pollen-tube inserted within the micropyle. 



Fig. 42 & 43. A seed of a species of Colocynth from the Pampas of Buenos Ayres, seen in front and 

 sideways. 



Fig. 44 & 45. The same magnified, showing its hollow hilum at/. 



Fig. 46. The same seen from below, showing the peripherical zone and the basal hilum. 



Fig. 47. A longitudinal section of the same : — a. the crustaceous tunic ; b. a nearly annular and perfectly 

 free raphe lying between the crustaceous covering and the true integuments of the seed : it 

 first passes through a tubular channel c on one side of the base of the crustaceous covering, and 

 takes its course all round the enclosed seed, and again arrives at the base, disappearing in the 

 loose cellular pith that fills the hollow space within the hilum ; the spiral threads appear to 

 separate here and again unite to form a kind of suspensor to the seed ; <^. is a reddish-coloured 

 areole on the summit of the integument, at the spot where the chalaza should exist according 

 to ordinary rule, but the raphe certainly does not enter or terminate here, but passes freely 

 over it, like a bisecting line ; e. is another dark-coloured areole around the neck of the suspensor 

 at the opposite extremity, which appears to unite with the raphe, for it contains spiral vessels ; 

 /. is the hollow chamber within the hilum filled with loose pithy cells. 



Fig. 48. The same viewed from the summit, showing d the false chalaza, and the manner in which the 

 raphe crosses it. 



Fig. 49. The raphe detached, apparently connected by very minute threads with the neck of the 

 suspensor. 



Fig. 50. The spiral vessels of the raphe highly magnified. 



Fig. 51. The seed invested by the testa and tegmen, both very thin membranes: d. the false chalaza; 

 e. probably a true chalaza. 



Fig. 52. The basal termination or neck of the two investing integuments, which are distinct and separable ; 

 the outer one is the testa ; the inner one only is marked at e with a dark areolar spot, from 

 which the spiral vessels are extended, and this is probably the true chalaza. 



Fig. 53 & 54. The embryo seen in front and sideways. 



Fig. 55. The same with one of the cotyledons removed, to show its nervation. 



