Scientific Intelligence — Zoology. 381 



menon, and I may therefore be permitted to generalise. The 

 Batrachians have also afforded me some examples of this descrip- 

 tion, although in general they are all oviparous. Nevertheless 

 a genus resembling the Rhinella of Fitzinger, and of which seve- 

 ral species, rather prettily marked, form part of my collection, 

 is constantly viviparous, and therefore increases the proofs of a 

 fact which is rendered more remarkable by the circumstance 

 that all the examples occur in a radius of two or three leagues 

 only. 



19. On the Changes which the Stomachs qf'Crahs undergo dur- 

 ing the period of casting their Shells. — A very accurate account 

 of these changes is given by Dr K. E. V. Baer, in the sixth num- 

 ber of Miiller's Archiv 1834. Crabs, it is well known, change 

 their shells at a certain season of the year ; and it is a very old 

 opinion that they change their stomachs at the same time, a new 

 stomach being formed round the old, which is digested by the 

 recently developed organ. Baer has proved that the crab's sto- 

 mach consists of two coats ; one inner, which in every respect 

 may be compared to a callous, horny epidermis, and which is 

 destitute of vitality ; and an outer or containing coat, transpa- 

 rent, but sufficiently strong and vascular. The inner coat, as 

 it is well known, consists of various and very curious parts, 

 some resembling boney plates, others'compared to teeth ; now 

 at the period when the crab changes its skin, it likewise casts 

 the inner coat of the stomach, and on this account this pro- 

 cess, analogous to the moulting of birds, and to the renewing of 

 the hair in quadrupeds, is in the crab attended with very great 

 constitutional disturbance, and a total interruption of the diges- 

 tive function. Baer relates very accurately the changes which 

 the stomach undergoes preparatory to the casting of its inner 

 coat. It would be beside our present purpose to follow him in 

 this description, however interesting. Some things he mentions 

 are, however, specially worthy of remark ; in the first place the 

 softer parts of the old epidermis or inner coat of the stomach are 

 very rapidly digested in the stomach, as soon as it has recovered 

 its functions, and has, which it does quickly, formed a new lin- 

 ing on its inner surface. But there are other harder parts that 

 cannot be so readily digested and dissolved, and which are other- 

 wise disposed of. The hard and hollow bones, populary termed 

 VOL. XXr. NO. XLII. — OCTOBER 1836. c c 



