4*2 ILLUSTRATIONS OF SOUTH AFRICAN ZOOLOGY. 



The second memoir is " On the Brachyurous Decapod 

 Crustacea brought from the Cape by Dr. Smith," and con- 

 tains descriptions of twenty-three new species. Instead how- 

 ever of giving us a sketch of the primary distribution of the 

 Crustacea, we have the debateable question of the metamor- 

 phoses of these animals introduced, apparently for the pur- 

 pose of telling us that Mr. J. V. Thompson has merited well 

 of science for his researches, " which is more than can be said 

 of any of those persons who, by crude inferences, but never 

 by direct observation, ventured to attack him." Can Mr. 

 MacLeay be ignorant that Rathke has most elaborately traced 

 the developement of the embryo cray-fish ? — That Westwood 

 has dissected the ova of the land crab of the West Indies ? — • 

 And that Rathke has recently asserted that "as to the 

 Decapods, so far as I have examined their developement, I 

 must deny the assertion of Thompson : and of them I can say 

 nothing less than that at the end of their existence in the egg 

 they have exactly the same aspect, and are as fully develop- 

 ed, as the full grown individuals." — (Annals Nat. Hist. 1837). 

 If these be not direct observations, — or if they merit the term 

 of "crude inferences," we would ask what kind of observa- 

 tions Mr. MacLeay would require ? 



Mr. MacLeay divides the Decapods into five tribes, — Te- 

 tragonostoma and Trigone-stoma (forming the Brachyura), and 

 Anomura, M.E., Sarobranchia, and Caridea, Latr., (forming 

 the Macroura. Each of the tribes Tetragonostoma and Tri- 

 gonostoma is divided into five stirpes, which are placed op- 

 posite to each other from analogy ; but nothing appears more 

 arbitrary than the adoption of their analogous characters, for 

 instance, Pinnotheres and Droniia, or Cancer and Corystes, 

 are as unlike as can well be conceived, and yet they are op- 

 posed to each other. As to the genera and other subordinate 

 divisions, the author constantly expresses his inability to de- 

 cide upon them, from not being acquainted with a sufficient 

 number of species. 



The third memoir is "On a new species of Cerapterus" 

 but it contains a monograph of the genus, so far as Mr. Mac- 

 Leay was acquainted with the species ; and also observations 

 on the family (Paussida) to which it belongs. To these Mr. 

 Westwood has published a reply in the last number of the 

 * Entomological Magazine,' in which he has described a fifth 

 species, not contained in Mr. MacLeay's monograph. 



We cannot conclude without alluding to the beautiful ex- 

 ecution of the four plates with which this part is embellished 

 from the pencil of Mr. C. Curtis, although they are destitute 

 of those structural details of the parts of the mouth, which 



