March 10, 1899.] 



SCIENCE. 



367 



cells have basal nuclei aud cytoplasm filled 

 with fine granules; their distal ends extend 

 outward to a minute pore at the extremity 

 of the flask. After the discharge of their 

 contents the central cells appear shriveled, 

 and it is probable that the whole organ is 

 soon afteinvards lost. Individuals lacking 

 one or both flask-organs are frequently ob- 

 served. After being lost, the structure is 

 reformed in the same position. It arises as 

 a conical thickening of the ectoderm, of 

 which the central cells take on a glandular 

 function, and the lateral ones form the epi- 

 thelial covering. Similar organs have not 

 been described as occurring in any other 

 endoproct. The function of their secretion 

 is unknown. 



On the outer surface of each tentacle just 

 at the margin of the lophophore there is a 

 single large cell which forms a slight pro- 

 tuberance. Its nucleus is large and situated 

 near the deeper surface ; the cytoplasm 

 shows a number of delicate lines extending 

 through it perpendicularly toward the free 

 surface, which is covered by a thickened 

 portion of the cuticula, having the form of a 

 flattened disk or of a saucer with its concave 

 surface outward. The observation of the 

 living animal shows that these structures 

 are unicellular suckers or organs for attach- 

 ment by means of which the little creature 

 fixes itself by the margin of its expanded 

 lophophore while changing the position of 

 its foot attachment. 



The reproductive system of L. Daven- 

 porti presents the rare condition of pro- 

 terogynic hermaphroditism. Both kinds of 

 sexual products arise in the single pair of 

 gonads, the ova being formed before the 

 sperm. The evidence for this consists in 

 finding in the same individual a functional 

 ovary on one side of the body, while the 

 gonad of the other side contained, together 

 with an evidently degenerating ovum, a 

 mass of cells showing various stages of 

 spermatogenesis up to the mature sperma- 



tozoa with tails. Animals which are func- 

 tionally males are relatively few during the 

 summer months. 



Buds remain attached to the parent till 

 well matured. They vary in number from 

 1 or 2 to 1 2. Abnormal buds lacking tenta- 

 cles, digestive organs, reproductive system, 

 etc., are not infrequently present. They 

 consist of a small rounded body borne on a 

 slender stalk. The proximal side of the 

 lophophore margin forms a blunt projection, 

 against which the rest of the margin can be 

 opposed, thus closing the atrial cavity. The 

 epithelium lining the atrium is composed of 

 large glandular cells. The relation of these 

 buds to the parent is not different from that 

 of the normal buds, nor does their attach- 

 ment persist longer. They appear to be in- 

 capable of leading an independent existence 

 and have no known function. They are 

 probably manifestations of a tendency to 

 produce modified members of the colony 

 comparable with the avicularia of certain 

 Ectoprocta, a tendency derived from stock- 

 building ancestors and which has not yet 

 been eliminated. According to this hypothe- 

 sis we must regard the non-colonial habit of 

 life of Loxosoma as secondarily acquired, 

 perhaps in adaptation to its semi-parasitic 

 or commensal mode of life, not, as has been 

 assumed heretofore, as a primitive condi- 

 tion. 



Embrj'os are present, attached to the 

 ' mammary organ ' of the parent during 

 July and August. On the embryo a pair of 

 buds arise very early and are fully formed 

 by the time it becomes free from the parent. 

 Soon after the buds separate from it the 

 embryo perishes without undergoing a meta- 

 morphosis. 



On the Motor Reactions of Paramecium. H. 



S. Jennings. 



The paper was an analysis of the 

 mechanism of reactions to stimuli in the cili- 

 ate infusorian Paramecium. To all classes 



