46 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the gills from above. In this group the photophores arc all identical 

 in structure and are quite immovable, though some of them are borm- 

 on short thick stalks, that they may bear more directly downward-. 

 They apparently increase in number even after the animal has reached 

 maturity. In Acanthephyra the organs differ in complexity according 

 to their position. There are twelve highly-developed organs, each 

 placed so that the light it produces is thrown directly downwards. One 

 is situated on the distal and external aspect of the protopodite of each 

 pleopod, and one behind the protopodite of each uropod. A dark violet- 

 blue streak on each side of the inner wall of the carapace immediately 

 behind the last pair of thoracic legs, is evidently from its structure also 

 a photophore, though it is less highly specialized than those at the base of 

 the pleopods. In addition, there are very numerous pigmented spots. 

 which the observer agrees with Coutiere in regarding as simple aggrega- 

 tions of luminous cells. The brilliant scarlet-red colour characteristic 

 of deep-sea Decapods is quite undeveloped in the neighbourhood of 

 the photophores. The more complex photophores appear first, the earliest 

 known larva already possessing the twelve organs. Fresh spots of blue 

 pigment appear after every moult ; in the largest individual examined 

 they reached the number of 147. The great majority of animals which 

 possess photophores live on the surface or in intermediate depths. 



Abnormal Cheliped of Lobster.* — Leon J. Cole describes an inter- 

 esting abnormality in the cheliped of a lobster (Homarus amerimnus)- 

 the abnormality consisting of a double extra claw. While the extra part 

 actually separates from the normal propodite, it is shown that the effects 

 of the doubling may be traced to the base of the leg. It is further 

 shown that the conditions in this appendage illustrate almost diagram - 

 matically the " rules of secondary symmetry " formulated by Bateson, 

 if allowance be made for the effects of the torsion which occurs in the 

 normal lobster cheliped, and the mechanical conditions which may 

 modify such torsion. Other similar abnormalities are discussed. 



Heterocuma.t — W. T. Caiman describes an immature female of 

 Heterocuma sarsi Miers from the Straits of Korea, and makes some 

 remarks on the genus, which occupies an interesting position among 

 Cumacea. It agrees in some respects with Gumopsis, among the 

 Bodotriidae, and in some ways with Vauntompsonia ; it seems to make 

 clear that the line of separation between Bodotriidfe and Vauntomp- 

 soniidae can no longer be maintained. 



Monograph of Phyllopoda Anostraca.J — Eugene Dadayde Dees has 

 completed an elaborate monograph on this sub-order of Phyllopods. 

 Among the extant families the Polyartemiidae, Branchipodidaa, and 

 Streptocephalidas have well-defined boundaries. The uniformity of the 

 family Branchinectidae is interrupted only by the genus Artemiopsis, 

 which has a penis of divergent structure. Much importance cannot be 

 attached to the presence of eight segments in the abdomen of Artenm 

 and Artemiella, or to the two branchial lamella? in Branchinectella. The 



* Biol. Bull., xviii. (1910) pp. 252-68 (9 figs.), 

 t Ann. Nat. Hist., vi. (1910) pp. 612-16 (1 pi.). 

 % Ann. Sci. Nat., xi. (1910) pp. 91-489 (84 figs.). 



