45-4 SUMMARY OF CURRENT RESEARCHES RELATING TO 



these three ganglia are very fully discussed. The posterior portion 

 (if the visceral nervous system is formed in Macrura by nerves which 

 arise from the last ganglion of the ventral chain, and from the 

 1 tranches which innervate the telson. In Brachyura the posterior portion 

 of the visceral nervous system comes from the single ventral concentration 

 of ganglia and from the two median nerves passing back from this. 



Development of Crayfish.* — Benedykt Fulinski describes the origin 

 of the mesoderm, distinguishing two kinds — the nauplial and meta- 

 nauplial (primary and secondary of Reichenbach). He also deals with 

 the vascular system. The heart-wall consists of two layers of cells, 

 the outer adventitia and the inner muscularis ; both arise from the 

 visceral mesoderm ; no internal endothelium is discernible. The cavities 

 of pericardium, heart, and blood-vessels must be regarded as remains of 

 the blastocoele. The vessels arise in the visceral mesoderm as gutter- 

 like primordia, in part independently of the heart, in part as outgrowths 

 of its wall. These distal and central primordia of vessels meet to form 

 blood-vessels. The sternal artery is at first paired, but the right or the 

 left component degenerates. The blood-cells are partly mesodermic and 

 partly endodermic in origin. 



Cambarus montezumse.f — E.A.Andrews makes some notes on 

 this Mexican crayfish, which are of interest in themselves and in con- 

 nection with Ortmann's theory that all the species of Cambarus may be 

 derived from ancestors once living in the Mexican region. The sexes 

 seem to be about equal in number : in the lot of 179 purchased in the 

 market of the city of Mexico, 91 were males, and S8 females. Forty-four 

 females had the seminal vesicle on the right side of the body, and 44 

 were sinistral. The first pleopods are absent in the females. The 

 attached larva? differ from those of other species in the perfection of their 

 sensory clubs, in the size of spinules, dentation of mandibles, and per- 

 fection of the last pleopods. They support the view that the early larvae 

 of Cambarus have degenerated from more active forms in connection 

 with a life of dependence upon the mother. 



Regeneration in Asellus.J — Margarete Zuelzer has studied in 

 Aselhis aquatkus the influence of regeneration on the rate of growth. 

 The animal can re-grow its antenna?, walking legs, and furca. The new 

 parts appear after the first moult after the amputation, and have the 

 normal size after the third moult. During the regenerating period there 

 is a hastening of the moultings. 



New Marine Isopod.§ — E. G.Racovitza describes Anoplocopea hansmi 

 g. et sp. n., an interesting new Sphaeromid from the Gulf of Ajaccio. It 

 is related to Campecopea and to the cavernicolous Sphaeromids, which 

 Hansen has ranked in the section Monolistrini. 



* Zool. Anzeig., xxxiii. (1908) pp. 20-8 (6 figs.). 



t Op. cit., xxxii. (1908) pp. 665-9. 



X SB. Ges. Natur. Freunde Berlin, No. 9 (1907) pp. 283-4. 



§ Arch. Zool. Exper., viii. (1908) Notes et Revue, No. 3, pp. lxxxiv.-xc. (1 fig.). 



