392 NOTES AND MEMORANDA. 



meeting, subjects admissible for Papers, &c. &c., will, of 

 course, he settled at tlie preliminary meeting. 



" (Signed) J. W. Groves, 

 " St. Bartholomeiv' s Hospital, Smithfield, E.C. 

 " To wbom all communications should be addressed." 



Models of Vertebrate Blood-corpuscles. — A series of twelve 

 models in a case is to be bad from Herr G. Klautscb, assis- 

 tant in tlie anatomical institute of Halle, for six tbalers, 

 illustrating the relative dimensions of the red blood-corpuscle 

 in various vertebrata. Prof. Welcker, in ' Schultze's Archiv,' 

 3rd part, 1872, gives an account of the physiological and 

 zoological facts which may be rendered evident by the use of 

 these carefully prepared models. All the models of the 

 corpuscles are prepared on the same scale, namely, five thou- 

 sand times the natural size. The animals represented are 

 musk-deer, goat, llama, man, chaffinch, lizard, frog, proteus 

 and tench. 



The following are abstracts of communications made to the 

 Biological Section of the British Association at Brighton : 



1. On the Structure and Development of Mitraria. By Prof. 

 Allman, F.P.S. — Several specimens of the remarkable larval 

 form, to which John Miiller gave the name of Mitraria, were 

 obtained by Prof. Allman in the Gulf of Spezzia, and were 

 made the subject of careful study of structure and develop- 

 ment. Mecznikoff had recently examined another species of 

 the same form, and the author was enabled to confirm the 

 main result arrived at by him, that Mitraria Avas the larval 

 form of an annelid. In some fundamental points, however, 

 regarding the process of development, his observations did 

 not agree with those of the Bussian zoologist, while in 

 structure there are some important features Avhich have not 

 been described by either Miiller or Mecznikoff, diflferences 

 which may, in some cases at least, depend on actual dif- 

 ferences between the species examined. 



The nervous system is well developed, and consists in the 

 princijDal central portion of a large quadrilateral ganglion, 

 formed by the union of two lateral ones, and situated on the 

 summit of the transparent dome-like body of which the larva 

 mainly consists. From this two very distinct cords are 

 sent downwards, so as to form a pair of commissures with 

 two small ganglia, which are situated at the opposite side of 

 the alimentary canal. Besides these, two other small ganglia 

 exist in the walls of the dome, at the oral side of the great 

 apical ganglion, and two similar ones at the ab-oral side. 

 These send off numerous filaments, which dive at once into 



