28 SUMMARY OF CURRENT RESEARCHES RELATING TO 



taceans) and conveying it to the mouth. There is budding from the 

 penultimate segment, followed by fission. 



Polian Tubes in Sipunculus.* — F. Ladreyt has studied the two 

 tubes which lie dorsally and ventrally on the oesophagus of Sipunculus 

 nudus opening anteriorly into the peribuccal sinus, and posteriorly with 

 blind ends at the beginning of the intestinal coil. They are much more 

 complex than has been supposed, and show several differentiated regions : 

 (1) A haematolytic region (posterior part of the ventral tube) ; (2) a 

 lymphogenic region (anterior part of the gland associated with the 

 dorsal tube) ; (3) an excretory region (posterior wall of the gland). 

 They may be regarded as lympho-renal organs. 



Regeneration of Head End of Ophryotrocha puerilis.t — C. Czwi- 

 klitzer reports some striking cases of regeneration in this Annelid. 

 After removal of the first segment, in one case, degenerative processes 

 set in for six weeks ; there was a loss of cirri, setae, and most of the 

 parapodia ; then degeneration stopped, and a week later there was a 

 complete regeneration of all the lost parts. If the first segment is 

 removed, the second may take on the characters of the head, to some 

 extent at least. When the first two segments were removed, there was 

 no regeneration. The first segment can repair its own minor injuries 

 very rapidly. 



Species of Polynoinae.} — L. Alaejos y Sanz gives a descriptive 

 account of some species of Polynoinae from the coasts of Santander. 

 Among others described and beautifully figured are the following : Lepi- 

 donotus clava, Halosydna gelatinosa, Hermadion pellucidum, Harmothoe 

 spinifera, and five other species of Harmothoe. 



Regeneration in Annelids. § — E. Schultz, in the course of a long 

 discussion of the various modes of regeneration which occur in Annelids, 

 emphasises the fact that " un-differentiation " up to a certain limit is a 

 general preliminary process. Before re-differentiation (sometimes on a 

 new line) occurs, there is this process of " un-differentiation." Morpho- 

 genetic processes are reversible. Some interesting experiments on 

 starving Planarians (Planaria lartea) show that many organs and cells 

 may return to their embryonic level. 



Japanese Palolo.|| — Akira Izuka gives an account of some of the 

 internal structures of Ceratocephale osaivai, the Japanese Palolo. He 

 discusses the circulatory system, the nervous system, and the nephridia, 

 which are essentially the same as those of Nereis diversicolor described 

 by Goodrich. 



Philippine Gephyreans.f — I. Ikeda reports on some Gephyreans 

 ■collected by Professor B. Dean at Southern Negros (Philippine Islands), 

 including Phascolosoma quadratum sp. n., Phymosoma deani sp. n., and 

 Thalassemia manjuyodense sp. n. 



* Arch. Zool. Exper., iii. (1905) Notes et Revue, ccxv.-ccxxii. (4 figs.), 

 t Arch. Entw., xix. (1905) pp. 140-7 (7 figs.). 



t Mem. R. Soc. Espafi. Hist. Nat., iii. (1905) pp. 5-76 (12 pis. and 5 figs.). 

 § Trav. Soc. Imp. Nat. St. Petersbourg, xxxiv. (1904) pp. 1-137 (5 pis. and 5 figs.). 

 || Annot. Zool. Japon, v. (1905) pp. 238-52 (1 pi.). 

 H Tom. cit., pp. 169-74 (1 pi.). 



