616 SCIENTIFIC RECORD FOR 1884. 



of formation. The posterior secreting portion of the foot always retains 

 the same form in the first case, whereas in the second we see it from 

 nearly circular become almost straight." {Comptes Rendus Acad. Sci., 

 1884, Jan. 28, p. 236; Ann. &'Mag. Xat. Hist. (5), Xiii, pp. 304-300; Arch. 

 Zool. Uxper. et Gen. (2), iv, pp", 869, 870; Rev. Set., xxxw, pp. 343, 344; 

 J. R. M. S. (2), IV, pp. 869^ 870.) 



Geplialopods. 



Development of the Gills in Gephalopods. — The development of the gills 

 in Cephalopods has, until recently, been but little, if at all, known. The 

 subject was investigated in 1884 by M. L. Joubin. It seems from 

 his investigations that "the branchiae of the embryo make their appear- 

 ance at the beginning of the development in the form of two small buds, 

 situated symmetrically with relation to the anteroposterior plane upoit 

 the middle of what will eventually become the posterior wall of the 

 pallia! cavity. The bud, produced by a pushing force of the epithelial 

 layer by the cells of the subjacent layer, soon elongates and forms a 

 small, well-differeutiated eminence, rounded at the apex and attached 

 by a broad base." Xo vibratile cilia, such as line the pallial cavity, 

 were detected. "The bud afterwards flattens so as to present two sur- 

 faces: a posterior one, applied against the visceral mass, and an anterior 

 one, which is subsequently covered by the mantle which bounds the re 

 spiratory cavity superiorly." 



Upon this Mttle lamina "a first horizontal fold appears towards the 

 middle, then a second nearer to the point, then a third still nearer the 

 free extremity, and so on. These folds form depressions upon one of 

 the surfaces corresponding with elevations upon the other surface ; the 

 branchial bud has, therefore, become an undulated lamina; gradually 

 other folds appear, always toward the point, while the whole organ at 

 the same time increases in dimensions." 



Of the vessels which form the branchia, "the one which conveys the 

 blood to it appears early at the commencement of the formation of the 

 laminse; it occupies nearly the center of the organ, and is comprised 

 within the base of the laminae and the gland of the branchia, which is 

 also distinctly marked at this period. The efferent vessel is formed 

 upon the crest of the branchia and on the outer border of the laminae; 

 it is undulated like the parts which bear it, and issues from the branchia 

 at the base, to be continued by the auricle of the heart." {Comptes Ren- 

 dus Acad. Sci., 1883, Xov. 12, p. 1070; Ann. & Mag. Nat. Hist. (5), xiii, 

 pp. 67-69.) 



PROTOCnORDATES. 



Tunicates. 



Development of Salpa. — Much has been written about the development 

 and morphology of Saljja, but some obscurity still hangs over the sub- 

 ject. The group has been investigated recently by Prof, ^y . Salensky, 



