372 Miscellaneous. 



the digestive sac of other moUusks, it may interest your readers to 

 be informed that the common scallop {Pecten maximus) now in sea- 

 son, and therefore easily obtained, contains a richer assemblage of 

 the most beautiful siliceous carapaces of animalcules than any other 

 of the mollusca hitherto noticed. 



So abundant and diversified are these forms in the scallop, that a 

 few grains of the undigested contents of the stomach, properly pre- 

 pared and mounted on a glass slide, exhibits many of the species 

 usually found in the Richmond earth, and indeed could not be readily 

 distinguished from a similar preparation of the fossil forms. 



Another remarkable fact, also noticed in the ' Medals' (see p. 233), 

 that of the occurrence of the mineralized bodies of Polythalamia, is 

 fully confirmed ; and when the eye of the observer becomes accus- 

 tomed to the appearances presented by remains of this kind, they will 

 be found abundantly in most chalk flints. I discovered one species 

 in an atom of flint, in which the entire body of a Rotalia, except that 

 part of it which occupied the outer cell, is as beautifully preserved as 



j that of an insect in amber. 



L^) I am, Gentlemen, yours obediently, 



Hamlin Lee, 

 Chester Square, Pimlico, April 21, 1845. 



H^MATOCOCCUS SANGUINEXTS, AG. 



In a valuable packet of Algae lately received from Prof. Kiitzing, I 

 was rejoiced to find a portion of an authentic specimen of the Alga 

 published under the above name in the ' Icones Algarum.' It belongs 

 to the genus Microcystis of Meneghini, and may vie with any of the 

 curious forms published in his monograph. It proves identical with 

 the Tobermorey plant of Mr. Harvey's ' Manual.' The Appin plant 

 has quite a different structure, and will be illustrated in Mr. Hassall's 

 work, which will we hope shortly be published. — M.J. Berkeley. 



Observations on the Formation of Capillaries, By E. A. Platner. 



As is well known, Schwann brought forward the view, that the 

 capillaries were developed from cells, the star-shaped appendages of 

 which became elongated. This view was adopted by Schwann from 

 observations on the tails of young tadpoles, in which he found star- 

 shaped cells between the capillaries, and from which he thought that 

 they united to form capillaries. Schwann however never observed the 

 actual formation of capillaries from these cells, nor did it occur to 

 him that these cells are found in tadpoles of all ages, whilst, had his 

 view been correct, they would have been rare or entirely absent in 

 the older ones. During the past summer I have given my atten- 

 tion to this subject, and can now assert most positively, that capil- 

 laries are never formed from the stellar cells. From the examina- 

 tions which I made not only on young tadpoles, but also on young 

 tritons 1 — Ij centimetre long, capillaries do not appear to be 

 formed independently of the already existing vessels, but each new 

 capillary is a continuation of those already formed, as I subsequently 



