924 



SCIENCE 



[N. S. Vol. XXVIII. No. 730 



alogues. Twenty-five species were collected 

 by the Discovery. 



Among the small collection of echinoderms 

 was the Promachocrinus first obtained by the 

 Challenger, sis Holothurians, two species of 

 Antedon, three Echini, eight Starfishes, and 

 ten or eleven Ophiurans. The collection of 

 larvEe yielded the discovery of two pelagic 

 forms and of the brood-pouch in Cucumaria 

 crocea. A well-marked axial sinus and pore- 

 canal in the Cucumaria embryo is of im- 

 portance as definite evidence of a structure 

 about which doubt had previously existed. 



Two species of Myzostomidse are treated in 

 great detail. The sipunculoids comprise 

 about thirty specimens which were all small 

 and are considered as belonging to a single 

 species of Phascolosoma. 



The Actinians comprised six genera and 

 eight species, of which six are Antarctic, two 

 having been obtained at the Auckland and 

 Falkland Islands. 



The Tetraxonid sponges are exquisitely 

 illustrated with colored plates of the finest 

 quality. 



There are six forms of Tetractonellidse de- 

 scribed, of which two are new varieties. The 

 species are equally divided between the genera 

 Craniella Schmidt, and Cinachyra. Of 

 Monaxonellida there are forty-three species, 

 with four new genera. Of the species, when 

 obtained, twenty-two were new to science, be- 

 sides seven new varieties. 



The calcareous sponges collected comprise 

 eighteen species and one variety, out of which 

 six new genera and two new family groups 

 have been constituted. All but five belong to 

 the Heterocoela. In the discussion Jenkin 

 proposes a new arrangement, founded in the 

 main upon the classifications of Polejaeff and 

 Dendy. The most interesting features of the 

 collection are the large number of species con- 

 taining chiactine spicules; five new species 

 with " linked " flagellated chambers ; a sponge, 

 Megapogon villosus, with larger spicules than 

 any hitherto recorded for a calcareous species ; 

 the unusual development of the gelatinous 

 mesoderm in Leucandra gelaiinosa; and the 

 duplicate ovum, apparently a new form of egg 

 cell in Megapogon, raripilus, and Achramorpha 



nivalis. In the latter case the ovum appears 

 to be made up of two unequal parts. The 

 larger part is very similar to the ordinary 

 large ovum cell and contains a large trans- 

 parent nucleus and a small, strongly staining, 

 nucleolus. The smaller part appears to be a 

 multicellular structure, consisting of a large 

 inner cell surrounded by a sheath of small 

 cells, but it is possible it may be a single cell, 

 the large portion being the nucleus. The 

 inner cell contains two structures ; one 

 strongly staining like the nucleolus of the 

 larger part, the other a hyaline sphere packed 

 with about a dozen grains of one color, and 

 an odd one which stains a different shade. 

 The cells forming the outer layer have each a 

 nucleus and a nucleolus. This layer, or 

 sheath, in some cases surrounds the inner 

 sphere completely, in others only surrounds 

 the outer part, not existing between the inner 

 spherical cell and the twin half of the ovum. 

 It is possible that the smaller twin may be a 

 feeding cell for the nourishment of the larger 

 twin. 



All the species of calcareous sponges were 

 obtained at the winter quarters and in com- 

 paratively shallow water. 



W. H. Dall 



Hygiene and Public Health. By Louis C. 

 Parkes, M.D., D.P.H., University of Lon- 

 don, and Henry E. Kenwood, M.B. Edin., 

 D.P.H., London. Third Edition with Illus- 

 trations. 8vo, pp. 620 with 96 illustrations. 

 Philadelphia, P. Blakiston's Son & Co. 

 1907. 



The third edition of this valuable work 

 under the conjoint authorship has been care- 

 fully revised and brought up to date. The 

 book is divided into thirteen chapters and 

 deals in a very comprehensive way with Water ; 

 The Collection, Removal and Disposal of 

 Excretal and Other Refuse; Air and Ventila- 

 tion, Warming and Lighting ; School Hygiene ; 

 Soils and Building Sites; Climate and 

 Meteorology; Exercise and Clothing; Food, 

 Beverages and Condiments ; The Contagia ; 

 Communicable Diseases and Their Preven- 

 tion ; Hospitals — Disinfection ; Statistics ; 

 Sanitary Laws and Administration. 



