ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 613 



A scheme of the presumed affinities of the genera and species is sub- 

 mitted. 



Notes on Sipunculids.* — Marcel A. Herabel contributes the first 

 part of a series of notes on the comparative morphology, comparative 

 physiology, and "biostatics" of Sipunculids. The Priapulids are con- 

 sidered as the primitive types of Gephyreans from which the Echiurids 

 and the Sipunculids have arisen, the former diverging towards the 

 Annelida and the latter towards the Bryozoa. The structure of Sipun- 

 culids is discussed in relation to the mode of life, diet, habitat, &c, and 

 .an interesting contrast is drawn between Sipunculus nudus and Phasco- 

 losoma vulgare. This leads on to a somewhat difficult " biostatical " 

 discussion, in which the muscular differentiation in particular is mathe- 

 matically expressed. 



Endothelial Derivatives and Pigment-Bodies in Gephyreans.f — 

 Marcel A. Hernbel discusses the peculiar spherules seen inside living 

 blood-corpuscles of Phascolosnma vulgare. They increase in size, they 

 move, they fuse, they pass into the coelomic fluid. They seem to be 

 peculiar kinds of pigment-granules, which become inert as they become 

 large, and are finally eliminated. 



The blood-corpuscles multiply by direct nuclear division (Cuenot), 

 or by proliferation of certain regions of the endothelium. Herubel 

 ■discusses the amcebocytes and their role in accumulating pigment-masses 

 in the connective tissue of the alimentary tract, whence elimination into 

 •the lumen of the gut is effected. The fixed ciliated " urns " of P/tasco- 

 losoma and the free ciliated " urns " of Sipunculids are most important 

 agents in digesting or agglutinating useless or foreign bodies in sus- 

 pension in the coelomic fluid. 



Gonads of Hesione sicula.J — W. Bergmann has been able to trace 

 part of the history of the hermaphrodite reproductive organs in this 

 Polychajt. They are not noticeable except at the climax of the sexual 

 period. There seems to be protandry, the spermatozoa being formed 

 first. After these disappear the eggs are liberated into the ccelom, but 

 none were found fertilised. The gonads then degenerate and dis- 

 appear. 



Development of Metameres in Salmacina dysteri.§ — A. Malaquin 

 has studied the development of the sexually produced larva (" oozoite ") 

 of this Serpulid, and compares it with what he has previously observed 

 in the asexually produced form ("schizozoite"). AVhen the larva escapes 

 from the maternal tube, where it passes through its trochosphere stage, 

 it shows the outlines of the three regions of the adult worm : — («) the 

 cephalic region with a pair of eyes and strong cilia ; (b) the thoracic 

 region with three segments ; and (c) a greatly reduced abdominal region. 

 In front of the latter, which is practically only a pygidium, there is an 

 undifferentiated zone, where future segments arise. The subsequent 

 thoracic segments, 4th to nth, result from a transformation and incor- 



* Bull. Soc. Zool. France, xxviii. (1903) pp. 111-25 (2 figs.). 



t Comptes Iiendus, cxxxvi. (1903) pp. 1)71-3. 



X Zool. Anzeifr., xxvi. (1903) pp. 415-7. 



§ Comptes Kendus, cxxxvi. (1903) pp. 3S9-91. 



