730 SUMMARY OF CURRENT RESEARCHES RELATING TO 



dcntly suffers from delayed publication, since the not very recent 

 momoir by Frenzcl on the same subject was not seen by the author 

 imtil his results, which are corroboratory, were being published. 



As to the function of the glands, the author demonstrated the presence 

 of diastase, pepsinc, and trypsinc, of emulsionizing enzymes, of pigments 

 analogous to those of the bile. These substances were not free, but 

 incorporated in adipose drops, which probably lose their contents in 

 digestion and are reabsorbed. 



Effects of Lesions of the Supra-oesophageal Ganglia of the Crab 

 (Carcinus Moenas).* — M. L. Petit has been partly induced to study the 

 effects of lesion of the supra-oesophagcal ganglia of the Crab by their 

 curious habit of lateral locomotion. If the animal attempts to move 

 after the operation has been performed on the left side, it describes a 

 series of circles in the direction of the hands of a watch, but its head is 

 directed sometimes outside and sometimes inside the circle. It passes 

 from one to the other of these positions by a half-turn. There is the 

 same spoke-wheel movement which is observed in Mammals, when the 

 brain is injured ; but, whereas in them, the head of the animal is always 

 opposite to the axis of rotation, it may be opposite to, or turned to it in 

 the Crab. If the right supra-oesophageal ganglion be injured, the move- 

 ments of rotation are in the opposite direction to those of the hands of 

 a watch. 



Male Appendages on Females.! — Herr D. Bergendal describes the 

 occurrence of distinctly male copulatory appendages on female crabs. 

 In many cases there were no appendages on the first somite of the ab- 

 domen ; in other cases they were rudimentary ; in others spoon-shaped ; 

 in a few like those of the male. Herr Bergendal regards this abnor- 

 mality as due to inheritance from the male parent, and lays stress on the 

 fact that only the useless and normally rudimentary first pair of appen- 

 dages are thus modified, while the second pair which are functional never 

 exhibit modification. A fuller description is in course of publication. 



Eyes of Cymothoidae.l — Mr. F. E. Beddard has investigated the 

 minute structure of the eye in certain CymothoidaB. His chief con- 

 clusions are as follows : — 



The SerolidsB and Cymothoidse possess eyes which differ in certain 

 important particulars from the compound eyes of all other Crustaceans 

 as at present understood. The points of dift'erence concern the retinulje. 

 Each retinula consists, in the first place, of four (^SeroUs) or seven 

 (Cymothoidge) elongated cells resembling those of other Isopoda ; each 

 of these cells secretes a cbitinous body, the rhabdomere. In Cymothoa 

 (Bullar) the individual rhabdomeres retain their distinctness. In other 

 Cymothoidfe and in the Serolidre the rhabdomeres become fused to form 

 an axially placed rhabdom, which has often a complicated form, and in 

 which a large quantity of pigment is deposited. The Serolidse (not the 

 deep-sea species) and many Cymothoidee possess a pair of large hyaline 

 nucleated cells, surrounded by the other retinula cells. In the axis of 

 these, and inclosed by them (in the Serolidse), is a delicate fibre, passing 

 back as far as the ommatial membrane, and expanding anteriorly into a 

 conical body, which appears to penetrate into the axis of the rhabdom. 



* Comptes Rendus, cvii. (1888) pp. 278-9. 



t Ofvers. K. Vetensk. Akad. Forhandlingar, 1888, pp. 343-6. 



X Trans. R. Soc. Edin,, xxxiii. (1888) pp. 443-52 (1 pi.). 



