306 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Astacus fluviatilis, Parastacus, and in the genus Cambarus. To the list 

 which he gives and comments on, he adds four cases in Cambaras spinosus 

 and G. affinis. " It would appear that in the genus Cambarus at least, 

 hermaphroditic individuals are females, which, owing to some ambiguity 

 of the formative cells of the embryo, have developed to a greater or less 

 degree the characters of the opposite sex. The condition is a very rare 

 one, and is usually shown in the external organs only." 



Phylogeny of Crustacean Limb.* — J. Thiele makes some observa- 

 tions on this subject. He concludes that the primitive form which is to 

 be traced to the annebd parapodium might be regarded as a blade of two 

 segments, whose proximal part was imperfectly separated from the body, 

 and whose musculature was derived from it, while the distal division — 

 as yet unsegmented — carried a dorsal, leaf -shaped appendage. Such a 

 type is approached most nearly in the thoracic leg of Nebaliella. Here 

 the basale and endopodite are together homologous with the original 

 distal segment. 



Crustacea of the Forth Region. f — Thomas Scott gives a catalogue 

 of the Malacostraca, Cladocera, and Branchiura found in the basin of the 

 River Forth and its estuary. There are 19 species of Brachyura, 33 of 

 Macrura, 26 of Schizopods, 21 of Sympoda (Cumacea), 42 of Isopods, 

 and 145 of Amphipods, making a total of 286 Malacostraca. Of 

 Branchiopoda, 55 species are noted, and the second part of the catalogue, 

 which will deal with Ostracods (about 132 species), Copepods (about 300 

 species), and Cirripedia (about 13 species), will raise the total to about 

 786 species, which is a fine record of faunistic work in a limited Scottish 

 area. 



Variation-Study of a Decapod. f — Arthur Brozek has made a de- 

 tailed study of the variations in the external characters of Atyaephyra 

 desmarestii Joly, dealing especially with rostrum, spines, and all the 

 appendages. 



Monograph of North American Isopods.§ — Harriet Richardson 

 deserves to be congratulated on her monograph of North American 

 Isopods — including sea-shore, fresh-water, terrestrial, cavernicolous, and 

 parasitic forms. The tribes, or super-families, dealt with, are : — Tanai- 

 oidea, or Chelifera ; Cymothoidea, or Flabellifera ; Idotheoidea, or 

 Valvifera ; Asselloidea, or Asselota ; Bopyroidea, or Epicaridea ; and 

 Oniscoidea. While the object of the work is to give descriptions and 

 figures of the known species of North American Isopods, the author 

 has not forgotten the perennial interest of habits and behaviour, and she 

 has effectively completed a big piece of work for which many zoologists 

 will be grateful. 



Monograph on British Wood-Lice. || — W. M. Webb and C. Sillem 

 have done a useful piece of work in preparing this monograph of the 



* Zeitschr. wiss. Zool., lxxxii. (1905) pp. 445-71 (2 pis. and 1 fig.). 



t Proo. Roy. Phys. Soc. Edinburgh, xvi. (1906) pp. 97-190 (1 map). 



% SB. k. Bohm. Ges. Wiss., i. (1905) pp. 1-69 (32 figs., 2 tables). 



§ Bull. U.S. National Museum, No. 54 (Washington, 1905) liii. and 727 pp., 

 740 figs.). 



|| The British Woodlice : being a Monograph of the Terrestrial Isopod Crustacea 

 occurring in the British Islands. London (1906) x. and 54 pp., 25 pis. and 59 figs. 



