366 



SCIENCE. 



[N. S. Vol. IX. No. 219. 



found several well-marked forms of epider- 

 mal organs, one of which is characterized 

 by the presence of intracellular sacks or 

 ampullfe leading into anastomosing canals. 

 Such organs contain both sensory and glan- 

 dular cells, but in the gland cells alone are 

 found the intracellular sacks. 



These organs present several well-marked 

 conditions cori'esponding with different 

 stages of functional activit.y. One sugges- 

 tive condition shows the following details 

 of structure. In the iipper part of each 

 gland cell are two sacks lying one within 

 the other and separated by a considerable 

 space. This intervening space is traversed 

 by many delicate filaments connecting the 

 walls of the two sacks. The inner sack be- 

 comes continuous at its outer end, with a 

 narrow canal, while the outer sack is contin- 

 uous with a sheath surrounding this canal. 

 The several canals unite to form larger 

 canals, and there finally results one main 

 duct opening to the exterior. This duct is 

 surrounded by a broad sheath, which is a 

 continuation of the sheaths enveloping the 

 ampullae and primary canals. By the side 

 of the main duct, within its enveloping 

 sheath, is a large nucleus surrounded by a 

 clear area, which probably represents a 

 vacuole. Eegarding this nucleus the am- 

 pullae, canals and sheaths the following 

 hypothesis is offered. The sheath of the 

 main duct and its branches, including the 

 radial vesicles surrounding the ampullae, 

 together constitute a cell of very irregular 

 shape, a cell which in form may be com- 

 pared to a bunch of grapes with its stem. 

 This single cell contains the main duct, its 

 branches and their terminal ampullae, and 

 itself reaches down flask -shaped processes 

 containing the ampullae, which are embed- 

 ded in the outer ends of the surrounding 

 gland cells. The walls of the outer sacks, 

 and their continuations as the outer wall of 

 the sheath, represent the boundary of this 

 highly differentiated cell. 



27(6 Development of the Adhesive Organ of 



Amia. Jacob Eeighaed. (Presented 



for Miss Jessie Phelps.) 



The adhesive organ of Arnia consists of a 

 pair of semicircular or sausage-shaped ridges 

 forming together an incomplete ring on the 

 end of the snout of the young larva. Each 

 ridge is a row of six to eight epithelial cups 

 which open on the surface of the snout. 

 Their cells secrete a mucus by means of 

 which the animal attaches itself. 



The organ is formed in a very early stage 

 as a diverticulum of the fore gut. This 

 diverticulum subsequently divides into two, 

 each of which continues to communicate 

 for a time with the cavity of the foregut. 



Each of the two diverticula later sepa- 

 rates from the foregut, becomes elongated 

 and curved into the form of a semicircle 

 and divides into from six to eight closed 

 vesicles. The vesicles finally open to the 

 exterior and are thus converted into cups. 



After being functionally active for a time 

 the organ is pushed beneath the surface by 

 the thickening ectoblast, becomes infiltrated 

 with leucocytes, and finally disappears 

 (larvae of 20 to 25 mm.) without leaving 

 any trace behind it. 



The integumentary sense organs appear 

 in the neighboring ectoblast, quite independ- 

 ently of the adhesive organ. 



Dean's comparison of the cups of the ad- 

 hesive organ with the integumentary sense 

 organs is thus seen to be untenable. 



Notes on Loxosoma Davenporti. W. S. NiCK- 



EESON. 



A PAIR of flask-shaped glandular organs 

 is commonly present in the American spe- 

 cies of Loxosoma, attached by their bi'oader 

 rounded ends nearly opposite the lower end 

 of the stomach, one upon each side. Each 

 consists of a central core of 4 or 5 glandular 

 cells and a peripheral layer of flattened 

 epithelial cells continuous with the epithe- 

 lial body- covering of the animal. The gland 



