292 5. Entwicklungslehre. 



like material, in which there are many yolk-granules. Gastrulation takes 

 place by invagination, and as this process progresses, the contents of the 

 segmentation cavity actually migrate througk tke fundus of tke arckenteron 

 into the gastrula cavity. In this process the yolk-granules are broken up 

 into finer masses which can be traced in their course through the entoderm 

 cells. Lillie (Chicago). 



803) Oaskell, J. F., The action of X-rays on the developing Chick. 

 (Proceedings of Royal Society 83B,564. p. 305—310. 1911.) 



Doncaster (Cambridge). 

 894) Iseley, F. B., Preliminary Note on the Ecology of the Early 

 Juvenile Life of the Unionidae. 



(Biol. Bull. 20,2. p. 77—80. Jan. 1911.) 

 In the study of the life-history of the Unionidae the author distinguishes 

 the embryonic, the glochidia, the parasitic, the early juvenile and the adult 

 as distinct periods for separate and special study. The early juvenile is the 

 least known, that is the period after parasitism until the young mussei is 

 about fifteen millimeters in length. The author had 32 specimens a material 

 representing nine species. All were attached to rocks and pebbles by a func- 

 tional byssus. All were found in rather swiftly running water with a bottom 

 of gravel and rocks. It is probable that those that drop from the host in 

 shifting sand or mud do not survive. The average mussei does not travel 

 far up or down stream from the spot where it led its juvenile existence. 

 Such areas are centers of dispersal in the stream where they occur. 



Lillie (Chicago). 



805) Feit, E. P., Miastor and embryology. 



(Science 33,843. p. 302—303. 1911.) 

 Die pädogenetischen Larven von Miastor werden als vorzügliches Material 

 für embryologische Studien am lebenden wie fixierten Objekt empfohlen. Ihr 

 häufiges Vorkommen, ihre Lebenszähigkeit auch unter schlechten Bedingungen 

 und ihre Durchsichtigkeit machen sie dazu sehr geeignet. 



J. Schaxel (z. Z. Neapel). 



806) Coker, R. E. and Th. Surber, A Note on the Metamorphosis of 

 the Mussei Lampsilis laevissimus. 



(Biol. Bull. 20,3. p. 179—182. one plate. 1911.) 

 The glochidium of L. alatus has been observed byLefevre and Curtis, 

 who describe it as an „axe-head" glochidium bearing hooks not homologous 

 to those of the Anodonta type. L. capax has a similar glochidium, and in 

 L. laevissimus the same shape is observed but the hooks are w r anting. Other 

 members of the genus have glochidia of the ordinary type, and the remarkable 

 fact is that the usual grouping of the species in the genus does not correspond 

 to the facts of the embryonic anatomy. 



Some of these axe-head glochidia were found encysted in the gills of 

 Aplodinotus grunnicus, considerably increased in size, contrary to the 

 general rule that there is no growth in size during the period of parasitism. 

 The parasite as compared with the glochidium was nearly 3V2 times as long 

 and l 1 j 2 times as wide, the glochidium shell being seated like a saddle on 

 the parasite. Lillie (Chicago). 



807) Srdinko, J., Das schnelle Wachstum einiger Cucullienraupen. 



(Intern, entom. Zeitschr. Guben, 5,7. p. 51—52. 1911/12.) 

 Die Raupen von Cucullia thapsiphaga, verbasci und lychnitis wachsen 



