58 SUMMARY OF CUKKENT Kb:SP:A.KCHES RELATING TO 



Limulus corresponds more closely to the Vertebrate type. The micro- 

 scopic structure is described in detail, but it is difficult to give an 

 intelligible summary without a figure showing the discs, lines, and other 

 differentiations. 



«• Crustacea. 



New Zealand Sandhoppers.* — Charles Chilton describes three New 

 Zealand species of Talorchesfia, and gives a diagnostic key and excellent 

 figures. In the male of T. tellnris there is an extraordinary process on 

 the fifth pertBopod (hind margin of the carpus). There is a suggestion 

 •of dimorphism among the males, for there are two forms with very 

 different second gnathopods. It is possible, however, that the second 

 form should be ranked as a separate species. 



New Isopod's from British Gruiana.f — A. S. Pearse describes some 

 new species, and establishes a new genus, Circoniscus, which is closely 

 allied to Sphseroniscus Gerstaecker, but differs iu having only two 

 segments in the flagellum of the second antenna. 



Habits of Lepidurus viridis4 — E. M. Herriott has studied this 

 interesting Phyllopod, common in shallow pools in New Zealand. Their 

 sudden appearance is due to the rapid development of the " winter " or 

 ■" resting " eggs, which are able to survive desiccation for months. 

 When feeding they usually lie on their back, moving all their limbs. 

 They bite at the caudal setae of their neighbours, and devour the dead 

 bodies of their fellows. There is considerable diversity of coloration 

 and size. The exhausting process of moulting is described, and the 

 rapid movements— mostly with ventral surface downwards — are also 

 dealt with. 



Annulata. 



Dimorphism in a Polych8et.§— F. Mesnil and M, Caulleryfind that 

 ^pio martinensis is dimorphic. Some sets of eggs develop into a typical 

 Spionid larva of pelagic habit ; other sets develop within the spawn-mass, 

 directly and without any pelagic stage. In the second case there is 

 cannibalism or adelphophagy. The phenomenon requires further study ; 

 it seems to be similar to what Griard called poecilogony. 



Segmentation of Ovum of Protula meilhaci.|| — A. Soulier notes 

 that after the eight-cell stage there are two vertical cleavages in new 

 planes, at angles of 45° with the first vertical planes. The two planes 

 do not appear simultaneously, though, in general, the posterior ele- 

 ments are formed before those anteriorly. In the fifth stage there is 

 the same lack of simultaneity in the formation of two more cleavage 



• Trans. New Zealand Inst., xlix. (1917) pp. 292-303 (18 figs.). 



t Mus. Zool. Univ. Michigan, Occasional Papers, No. 46 (1917) pp. 1-8 (3 figs.). 



X Trans. New Zealand Inst., xlix. (1917) pp. 284-91. 



§ Comptes Rendus, clxv. (1917) pp. 646-8. 



II Arch. Zool. Exp6r., Ivi. (1916) Notes et Revue, No. 4, pp. 100-3 (6 figs.). 



