898 THE AMERICAN NATURALIST. [Vol. XXXVIII. 



and here are held in position by the exopods of the swimmerets 

 while the endopods, covered by slender filiform hairs, extend into the 

 mass of eggs. The pleopoda have powers of motion in two planes, 

 one fore and aft, the other oblique. By these motions the ends of 

 the hairs are brought in contact with the eggs which are thus pene- 

 trated by them, the hair passing in and out again. The egg itself 

 rotates and escapes injury. In this way numbers of eggs are impaled 

 or skewered on each hair. As development proceeds the chorion 

 stretches and gives rise to a stalk, which increases in length with 

 time. This process is also aided by the perivitelline fluid, which is 

 adhesive and sticks the chorion to the hair. After the egg is hatched 

 the egg shells and their stalks are cast off by molting the integument, 

 the outer layer of the hairs, together with the adhering shells being 

 cast with the rest of the 'skin.' The eggs are fastened only to the 

 hairs of the endopods, as these alone are smooth and filiform. The 

 hairs of the exopods are plumose or serrate, a condition which pre- 

 vents their perforating the eggs. 



Gardiner's Maldives. i — The third part of the second volume of 

 Gardmer's Report maintains the unusually high quality of its prede- 

 cessors. It contains six papers, of which three are written bv mem- 

 bers of the expedition and the three others by well known specialists. 



The Isopoda are treated by Stebbing in 23 pages. Thirteen 

 species are described, representing eight families. While some are 

 from the sea at moderate depths, two (a Corallana and a Limnoria) 

 are found in rotten wood in the lagoon, one (Cirolana) lives in tenta- 

 cles of a large tubicolous polychaete. A Cymothoa lives on the gills 

 of a parrot-fish. Tylokepon, n.g., is a bopyrid living on the gills of 

 Crustacea. Finally, a sphaeromid (Exospha^roma) and a Ligia are 

 representatives of two semi-terrestrial groups. 



lue Hydromedusaj are treated by Browne. The discussion of 

 the Anthomedus^t leads to a revision of the family Williada with 

 two genera. \\ ilha and Proboscidactyla, of which the latter onlv is 

 co^st^'of'^'x''^^'''" ^''^ Maldives. It occurs also on the east 



^^^^^ ^ ^'orth America and has several species notable for their 

 proc uction of medusa buds. Among the Leptomedusa^ is a five- 

 f^blimr^Mrv^r^''''- ^^""^'^"'^ g^""^ Pseudoclytia which Browne, 

 medus"" ^^'i^ves to have arisen as a sport. The Tracho- 



luec usa' are treated in synoptic fashion. A new species and a new 



