TRANSACTIONS OF SECTION D. 410 



his command ; and. without relinquishing the work himeelf , he wishee to point out 

 to others interested in such research work, that there is a probable trypansomic 

 disease here in England at present uninvestigated. 



2. Recent Discoveries in Mimicry, Protective Resemblance, &c, in African 

 Butterflies and Moths. By Professor E. B. Poulton, F.R.S. 



3. The Extinct Reptiles of the Oxford Clay of Peterborough. 

 By Dr. C. W. Andrews, F.R.S. 



TUESDAY, SEPTEMBER 5. 

 The following Papers were read : — 



1. On the Distribution of Trachea to the Scent Patches in Lepidoptera. 

 By Dr. J. A. Dixey, F.R.S. 



The circumscribed patches of scent-distributing scales which occur in the 

 males of many butterflies belonging to the group of Pierinse, are furnished 

 with a special supply of tracheae derived from a neighbouring so-called 'vein.' 

 This feature has been observed in members of the genera Colias, Teracolus, and 

 Catopsilia ; but not in Dismorphia, where similar patches are present. The 

 significance of this special supply of air-passages is doubtful, especially as the 

 ultimate tracheal branches have not been traced with certainty ; but the sug- 

 gestion is hazarded that their function may possibly be to assist mechanically 

 the liberation of perfume from the specialised scales of the patch, by the 

 impulse of air acting as a vinaatergo. 



2. The Annual Cycle of Changes in the Genital Glands of Echinocardium 

 cordatum. By Professor Maurice Caullery. 



From July to the end of the year the genital glands of this Echinoid are 

 almost entirely composed of large cells with parietal cytoplasm enclosing 

 numerous spherules of reserve substance and with a large vacuole containing a 

 hyaline liquid. In males these cells present, among the spherules of reserve 

 material, numerous spermatozoa, agglutinated into packets, which have been 

 ingested (phagocytosis) ; in females there are, between the cells, fragments of 

 ovules (cytoplasm or nucleus) in degeneration; at the periphery there are either 

 young ovules or small masses of spermatogonia. The growth of the genital 

 products is effected (in part owing to the presence of the reserve-laden cells) 

 at the end of winter, and the period of maturity, at Wimereux, extends from 

 April to the end of May, or even further. The reserve-containing cells are 

 gradually pushed towards the centre of the acini and disappear; but while in 

 some localities, such as Naples, the disappearance of these cells is practically 

 complete, at Wimereux they do not so fully disappear : there remains always a 

 certain amount of this tissue. There are thus, from the physiological aspect, 

 certain interesting differences. 



At the end of May there is a rapid and active change in the genital glands. 

 Up to that time there have been formed, in the testis, for instance, only sexual 

 cells closely appressed ; henceforward there are produced numerous cells, each 

 of which elaborates groups of granules and contains a large vacuole. This is 

 the new reserve tissue which has made its appearance and rapidly forms a 

 continuous peripheral layer. Soon, by the end of June, the sexual elements in 

 course of formation — young eggs or stages of growth of spermatozoa — exhibit 



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