96 Scientific Intelligence. 



ably thorough and exhaustive study of the forms of the diamond. 

 It is a study of peculiar interest, not only because of the value 

 and rarity of the specimens themselves, but also because of the 

 many peculiarities of crystalline structure which the crystals of 

 this species exhibit. The completeness of the present work will 

 be appreciated from the fact that 131 crystals have been exam- 

 ined, and besides the description in the text, the results are given 

 in 292 figures on 42 admirable plates. Many of these plates have 

 a thin paper cover, making possible the minute description of the 

 forms figured. In the case of the twin crystals, many of them 

 highly complex and extremely interesting, the figures are cleverly 

 colored so as to exhibit the relations of the different individuals. 

 The authors decide definitely in favor of the hemihedrism of the 

 diamond, a point about which there has been some difference of 

 opinion. As it is expressed, however, this hemihedrism is not 

 always distinctly shown ; or, in other words, the difference 

 between the two tetrahedrons is often not prominent. In the 

 case of an investigation of such thoroughness and minuteness, it 

 would be difficult to give an idea of the contents of the volume 

 without much detail of description, but attention is to be called 

 to the point that the rounded surfaces of the crystal form, and 

 the many peculiarities of the faces themselves, are treated very 

 fully with reference to the conditions of their origin. 



11. The British Tunieata ; an unfinished monograph by the 

 late Joshua Alder and the late Albany Hancock, edited by 

 John Hopkinson. Volume III, Aggregates (Ascidice Com- 

 posites). Pp. xii, 113 ; 16 plates, mostly colored. London, 1912 



(The Ray Society). — This volume completes the excellent mono- 

 graph prepared by the Secretary of the Ray Society from the 

 unpublished drawings and manuscript left successively by Alder 

 and Hancock at their death about thirty years ago. The two 

 earlier volumes of the series (see this Journal, xx, 469, xxiii, 398) 

 described the simple ascidians of the British coast, while the con- 

 cluding volume treats of the compound forms. The illustrations 

 by Alder, most of which are from colored drawings of the living 

 animals, are supplemented by others copied in colors from Milne 

 Edwards' well-known monograph. w. E. c. 



12. Ceylon Marine Biological Reports, Part VI, Nos. 20 to 

 22 ; Report on Certain Scientific Work elone on the Ceylon Pearl 

 Banks during the Yeetr 1911, with three plates and three charts ; 

 by T. Southwell and Lieutenant J. C. Kerkham, Colombo 

 (Government Printer), Ceylon, 1912. 



This report consists of three separate papers, two of which deal 

 Avith nautical notes and observations, while the third contains 

 descriptions of ten new species of cestode parasites of the marine 

 fishes of Ceylon. 



The announcement is made that because of the failure of the 

 pearl fisheries of the region during several recent years the labo- 

 ratory is to be abandoned and no further reports issued. 



