Miscellaneous. 485 



decreases in proportion as the appendicular region develops ; 

 further, in the former the palp and the iutermaxilla dwindle as the 

 galea (the sole directing portion) enlarges. 



These facts seem to be of such a character as to modify the classic 

 conception of the mandible ; fiirther, they permit a rapid extension 

 to other buccal organs. Such is the object of the researches on 

 which I am at present engaged, and of which I hope to give the 

 further results in a later communication. — Comptes Rendus, 1896, 

 tom. cxxiii. pp. 608-610. 



On the Hibernation of Clavelina lepadiformis, MiUler. 

 Ey MAT. A. Giakd and M. Caullert. 



Clavelina lepadiformis, Miiller, formerly somewhat rare on the 

 coasts of the Pas de Calais, is become very abundant on the 

 Bernard rocks, near Boulogne, since the establishment of the new 

 port. To any one who observes the pretty corms of this Synascidian 

 it is a very interesting problem to know how it is that the colonies, 

 sometimes as large as the fist, disappear entirely in the winter, to 

 reappear in the month of June in the following year, with the same 

 development and in precisely the same positions. One cannot 

 attribute the formation of these new corms to the proliferation of 

 the oozoVtes produced by the old ones, because, rapid though the 

 hudding of these oozoites may be, it could not suffice to produce 

 such large masses in so short a time. But if, towards the end of 

 September or in October, or even during the equinoctial tides of 

 the spring of the following year, one examines carefully the place 

 occupied by the vanished colonies, there will be found adhering to 

 the rocks numerous ramified and interlacing stolons, bearing here 

 and there little whitish glomeruli of a chalky appearance, the whole 

 constituting an ensemble which recalls well enough the general 

 aspect of a colony of Bryozoons of the genus BowerbanA'ia. It is 

 the form under which the Clavelina hibernates, reduced to tubular 

 stolons filled at certain points with reserve material. 



Nature of the Stolons.- — The stolons in which the reserve material 

 is accumulated are identical with those which during the summer 

 unite amongst themselves the different individuals of the corraus, 

 and on which are formed the ordinary blastozoites. They arise from 

 the lower part of the abdomen of the individuals. Often they 

 climb to the surface of these, and not infrequently the tunic of the 

 stolon is so united as to be continuous with that of the individual. 

 As, on the other hand, the stolons divide themselves into sections, 

 one often sees isolated fragments of them crammed with reserve 

 material, forming part at certain points with the tunic of individuals 

 of which the branchia and digestive tube have more or less com- 

 pletely disappeared. 



Like the normal stolons, the hibernating stolons enclose a pro- 

 longation of the epicardiac tube (" cloison stoloniale "), of which the 

 two faces are fused. 



Modifications of the Stolons. — At certain points more or less 

 regularly interspaced the stolouial tube produces numerous lateral 

 digitiform diverticula, forming the whitish glomeruli in which the 

 reserves are accumulated, and which may be compared with the 

 gemmides oi 8i)0iiges and the statoblasts of the Bryozoa. On these 



