320 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Variations in the Norway Lobster.* - - D. C. Mcintosh has 

 examined a large number of specimens of the Norway lobster {Nephrops 

 norvegicus), procured from Newhaven fishmarket or trawled in the 

 Firth of Forth and the Moray Firth. In regard to the relative size of 

 males and females, it was found that less than 1 per cent, of the females 

 and 30 per cent, of the males examined were over 16 cm. in length ; 

 while 20 per cent, of the males, as against 80 per cent, of the females, 

 were under 12 "5 cm.; so that in general the female adult is shorter 

 than the male. Of 5894 specimens only 703, or scarcely 12 per cent., 

 were females. It was found, however, that the proportion of females 

 was much greater in hauls taken with a smaller meshed net, and it is 

 suggested that the well-known scarcity of females in boxes procured for 

 laboratory purposes may be partly accounted for by the method of 

 capture. It was found that variation in the number and arrangement 

 of the male genital apertures was not uncommon. The normal aper- 

 tures were present in every case, but in 6 • 5 per cent, there were addi- 

 tional openings, the variation ranging from the normal two up to six. 

 These extra openings occur without any regard to bilateral symmetry. 

 The number of individuals showing abnormality decreases as the extent 

 of the abnormality increases. Particulars as to the material examined, 

 the number and extent of variations, etc., are clearly arranged in tables. 



New British Terrestrial Isopod.f — Alexander Patience describes 

 Trichoniscus linearis sp. n., from Kew Gardens, where it was found 

 under flower-pots along with Haplophthalmus danicus Budde Lund. 

 Another species, T. stebbingi, was found in the flower-pots, and six other 

 Trichoniscidas were taken at Kew on the same day. The new species is 

 at once distinguished from all the other British species of Trichoniscus 

 by its conspicuously linear form, approaching nearer to T. pygmceus, 

 G-. O. Sars, in this respect than any other member of the genus. 



Life-history of Sacculina.J — G-. Smith has experimentally infected 

 Carcinas mamas with this parasite and followed out the life-history. It 

 is briefly as follows. The eggs undergo maturation in the brood-pouch 

 and are self -fertilised. Development up to the nauplius stage proceeds 

 here ; the nauplii are expelled to the exterior and lead a free-swimming 

 existence for four days, undergoing four moults. The cypris stage is 

 reached on the fifth day, and after two or three days of free existence 

 the cypris larvae attach themselves by their antennules to a hair upon 

 any portion of a young crab, preferably upon the appendages. The 

 cypris casts off its thoracic appendages, the ectoderm draws away from 

 the shell and comes to surround a mass of mesodermal cells ; it secretes 

 a chitinous coat, and in this manner the Kentrogon larva is formed. 

 The cypris shell, including all the larval organs, is thrown off. The 

 embryonic cells of the Kentrogon, consisting of ectoderm and mesoderm, 

 pass through an ectodermal hollow dart into the haemoccele of the 

 crab, and are carried in the blood-stream till they reach the intestine. 

 They are inclosed in a thin chitinous cuticle. The Saccidina interna 



* Proc. Roy. Phys. Soc. Edinburgh, xvii. (1908) |pp. 129-42. 



t Ann. Nat. Hist., i. ser. 8„ pp. 280-2 (1 pi.). 



X Quart. Journ. Micr. Soc, li. (1907) pp. 625-32 (6 figs.). 



