No. 7. — The Structure and Developraent of the Antennal Glands 

 in Homarus americanus Milne-Edwards} By Frederick C. 

 Waite. 



CONTENTS. 



Introduction . . . . . 



Methods 



I. Structure in the Adult 



A. Gross Anatomy 



B. Finer Anatomy 

 II. Developraent . . . 



A. Historical Summary 



B. Development in the Embryo 



C. Development in the Larvae 

 (a) In the First Larva . . 



1. General Structure . . 



2. Histology 



PAGE 



151 

 154 

 157 

 157 



162 

 168 



168 

 172 



182 

 182 

 182 

 185 



II. Development, continued. 



(b) In Older Larvae ... 188 

 III. Theoretical Considerations . 191 



A. Homology of the Antennal 



Glands with the Ne- 

 phridia of Annelids . . 191 



B. The Number of Metameric 



Organs of this Nature in 



Crustacea 196 



Summary * 201 



Bibliography 205 



Explanation of Plates 210 



Introduction. 



The antennal glands of Crustacea have been the subject of much dis- 

 cussion ever since the first discovery (Hthem in Astacus by Rosel von 

 Kosenhof (1755, p. 321). The true relation of the parts of the organ 

 was for a long time overlooked, and the gland proper was considered as 

 distinct from the storage reservoir and duct to the exterior. The former 

 was supposed to be connected with the digestive tract, either as a sali- 

 vary gland or as the source of the gastroliths, while the latter was taken 

 for a sense organ, first as auditory, later as olfactory. Brandt ('33, 

 p. 64) showed that the parts which had been considered os two organs 

 of different functions really constituted a single structure. To this was 

 ascribed the function of hearing. 



All observations were confined to Astacus until Semper ('61) extended 

 his work to Lucifer. Shortly afterward Claus ('63) added observations 



1 Contributions from the Zo()logical Laboratory of the Museum of Comparative 

 Zoology at Harvard College, under the direction of E. L. Mark, No. 105. 



