ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 47 



e. Crustacea. 



Ferments in Crustaceans.* — J. Giaja found in Astacus leptodactylis 

 (as in the snail) a ferment called raffinase. This seems to be absent 

 in marine Crustaceans (as also in marine molluscs). Lactase, also present 

 in Astacus, was found, among marine forms, only in the lobster. In the 

 lobster, however, there was no trace of invertine, which was found in all 

 other Crustaceans experimented with. The gastric juice of Paliaurus 

 vulgaris, which acts on amygdalin, has no action on salicin. 



" Granny " Crabs.j — W. A. Herdman has a note on what the Port 

 Erin fishermen call " granny " crabs, though they are not necessarily old 

 nor female. They are caught in considerable abundance during July 

 and August, and are promptly killed, the impression being that they are 

 diseased. A " granny " crab, which may be of any size above 4 inches, 

 is generally female, and has a worn and dilapidated appearance, the 

 shell being pitted and stained with black, and the great claws corroded 

 and frequently broken. The surface is frequently overgrown with 

 barnacles and other foreign bodies. The men say that the flesh has a 

 strong bitter taste and a powerful purgative effect. There is, however, 

 in all probability nothing abnormal about these crabs. They are merely 

 individuals which are approaching the time when in every second year 

 a crab of this size will cast its shell. The practice of destroying them 

 is unwarranted. 



Autotomy in Grapsus. j — Anna Drzewina points out, in answer to 

 Pieron, that autotomy of the claw occurs without violent excitation in 

 specimens of Grapsus varkis, in which the oesophageal commissures 

 have been cut. She does not seek to deny the intervention of the 

 cerebral ganglia in autotomy ; they may have an excitatory or an inhibi- 

 tory action ; but the point is that their intervention is not indispensable. 



Autotomy in Decapods.§ — H. Pieron distinguishes between "evasive" 

 autotomy, which seems to him " voluntary " in the same sense as an 

 endeavour to escape is voluntary, and reflex autotomy, which is much 

 more general. The muscular contractions which effect autotomy in 

 Grapsus are of the same order as the normal locomotor contractions. 

 Voluntary or evasive autotomy is particularly well developed in Grapsus, 

 but it occurs elsewhere, for instance in hermit crabs. Reflex autotomy 

 is not universally distributed even among the Brachyura. 



Real Nature of Microniscidse.|| — M. Caullery has given experimental 

 proof of the view held by G. 0. Sars, that Microniscidse are really 

 stages in the life-history of Epicaridae, intermediate between the 

 Epicaridian and Cryptoniscian larva?. Although Bonnier persists in 

 regarding Microniscidas as a distinct family, Caullery thinks that the 

 position held by Sars is incontestable. In the case of Portuuion 



* C.R. Soc. Biol. Paris, lxxiii. (1907) pp. 508-9. 



t Liverpool Biol. Committee, 21st Report, 1907, pp. 25-6. 



X C.R. Soc. Biol. Paris, lxiii. (1907) pp. 493-5. 



§ Tom. cit., pp. 517-19. 



|| Comptes Rendus, cxlv. (1907) pp. 596-8. 



