ZOOLOGY AND BOTANY, MICKOSCOPYj ETC. 365 



The intracellular type obtains in what the author calls his first, 

 fourth, and fifth systems ; here the cells are attached to long stalks 

 and float in the coelom ; and thus it happens that the whole of their 

 surface is able to take up the necessary matter from the blood. In 

 connection with the consequent large secretion, secretory canaliculi 

 are developed, wliich make their way into the cells, surround the 

 plasma, and so afford a correspondingly large surface for excretion. 

 To this type a much greater secretory activity must be ascribed than 

 to that in which secretion is intercellular. In the so-called fourth 

 system we fiud that the intercellular spaces are very rare, and in the 

 first ( Bomhus) the free cells are arranged in acini. Both these arrange- 

 ments must be due to the large number of cells present. 



The author concludes that the so-called crop has, in honey-bees, the 

 function of, at times, completely shutting off the honey-stomach from 

 the chyle-intestine, while the small intestine forms the means of com- 

 munication between the latter and the rectum. The salivary glands 

 vary considerably both in genera and species, and it seems probable 

 that their functions are also very varied. While one system of glands 

 is formed within the propria of the first portion of the larval spinning- 

 glands, two others are derived from its efferent canals, and the other 

 two are fresh structures formed by an invagination of the epidermis. 

 The olfactory mucous gland of Wolff is salivary in function. 



Mimicry of Humming-birds by Moths.* — The striking resem- 

 blance in size, form, and movements, of the South- American Macro- 

 glossa Titan to humming-birds, which has been noticed by Bates, 

 Fritz Miiller, and others, and referred to the similarity in their habits, 

 is believed by Dr. Krause to be a case of protective mimicry, the 

 moths benefiting by their resemblance to the birds, which have few 

 winged enemies. The closeness of the resemblance is supposed also 

 to protect the moths from the humming-birds, which always give 

 chase when they recognize them. To do away with an objection that 

 might be urged from the similar appearance of European ilf a cro^Zo-fsce, 

 which have no Trochilidas to imitate, it is assumed either that these 

 birds occurred in Europe in late tertiary times, or that the moths are 

 recent importations from the new world. 



jS. Myriopoda. 



Systematic Position of the Archipolypoda.t — Dr. A. S. Packard, 

 jun., has some observations on the recent paper by S. H. Scudder on the 

 Archipolypoda, a group of fossil Myriopoda, from the Carboniferous 

 formation. These forms had a fusiform body largest near the middle 

 of the anterior half or third ; the head appendages were carried on a 

 single segment. Connected with each of the ventral plates of the 

 other segments are a pair of long jointed legs, with large spiracles 

 outside them ; the mouth is set transversely. Dr. Packard has lately 

 been studying the Lysiopetalid^e, " a rather aberrant and synthetic 

 family of Chilognatha," and he points out that Scudder must have had, 



* Kosmos, Nov. 1882. Cf. Science, i. (1883) p. 203. 

 t Amer. Natural., xvii. (1883) pp. 826-9. 



