Dr. W. B. Carpenter on the Development of Purpura. 127 



oblongis vel oblongo-cuneatis, pedicellis calyce longioribus, inter- 

 duin geminis, plerunique unilioris, calyce hreviter 5-dentato glabro 

 vel puberulo, corolla calyce duplo longiore anguste infundibuli- 

 fornii, stamiiiibus inclusis. — L. europceum, Linn, et aiict. ; lloyle, 

 111. ; L. mediterraneum. Dun. in DC. Prod. xiii. .523 (cum omnibus 

 variot.) ; L. Edyeworthii, Dun. in DC. Prod. xiii. 525 ; L. indicum, 

 Wight, Icones, t. l-i03. 

 Hab. in India prope Delhi, Royle ; Guzerat, Wight ; Sirhind, Edge- 

 worth ; Panjab ad Umritsir, T. Anderson. 



Folia glabra vel punctulata \-\ unciam longa. S{)inae axillares 

 nudfe vel foliosa; \-\ unciam longae. Flores gemini vel ssepius 

 solitarii e fasciculis foliorum. Calyx 5-dentatus eyathitormis 1-2 

 lineas longus, glaber. Corolla calyce longior infundibuliformis 

 4-0 lineas longa, roseo-alba. Filamenta filiformia inclusa inee- 

 qualia, uno ceeteris breviore. Antherse parvse ovatae, basi bifidae. 

 Stylus eylindricus, staminilius longior. Stigma orbiculare, capi- 

 tatum. Pollen in aqua globosum. Ovarium ovatum. Bacca 

 globosa parva. 



In India, special care is required to guard against the undue 

 increase of species, since in this country, besides difficulties 

 arising from want of books of reference, natural causes make 

 the determination of species more difficult than in Europe. One 

 of the most powerful of these is the sudden and complete change 

 of climate in many parts of the Peninsula of India, arising from 

 the periodical recurrence of the rainy season, which often alters 

 the flora from that of an arid plain to one consisting entirely of 

 a large number of tropical annuals. This climatic change also 

 tempoi'arily affects the appearance or ''habit" of the perennial 

 plants, causing a wonderful luxuriance of growth and alteration 

 of the foliage. To these changes Lycium ewopaum is fully ex- 

 posed. It is a native of dry sandy plains, where, before the 

 rains, it is stunted in all its parts ; but when the air and soil 

 become charged with moisture, an exjiansion of all its parts 

 takes place, fully accounting for the multiform characters of its 

 leaves, and the diversity in the length of the spines, &c. 



XII. — On the Development o/Purpura. By Wm. B. Carpenter, 

 M.D., F.R.S., F.G.S., F.L.S. 



To the Editors of the Annals of Natural History. 



July 20, 1857. 

 Gentlemen, 



My friend Dr. Dyster of Tenby (whose competency as an 

 accurate and well-informed microscopist is well known to every 

 naturalist who has visited that place) having applied himself 



