Mabch 27, 1914] 



SCIENCE 



475 



57-64 or average 64-69. The average date of 

 appearance is May 20, tlie earliest date May 11. 

 At the mating season the first finger of the male 

 becomes enlarged. The type of amplexation is 

 axillary. The breeding season extends from June 

 15-August 1, the average date of beginning of 

 ovulation being June 30. The female keeps in one 

 position more or less and lays a paneakelike film 

 of eggs on the surface of the veater. This film may 

 be from one foot to three feet in diameter. The 

 eggs are laid among brush, driftvpood, old stumps 

 in water, etc. During ovulation the prevailing air 

 temperatures are from 71-80; the water maxima 

 from 66-71. It takes only a few minutes to lay 

 the 12,000-20,000 eggs. The jelly is loose, the 

 animal pole black, the vegetative pole white. 

 There is no evident middle envelope. The eggs 

 usually hatch in 5-3 days because usually sub- 

 jected to a temperature of 65-80. The tadpoles 

 require two or more years of growth before trans- 

 formation. The relative smalMess of the eggs 

 (vitelli 1.2-1.7 mm. in diameter), the late deposi- 

 tion of the eggs, and the greater transformation 

 size required (53 mm. instead of the 9.6 mm. of 

 two or more winters in the larval stage. Besides 

 the toad) — all combine to make this form spend 

 other characters, the best external character is the 

 tail with regular round black spots, some of which 

 are dumb-bell-like in shape. The belly is straw- or 

 maize-yellow, not iridescent. Transformation 

 comes from July 18 to August 15 or months later. 



An Experimental Study of tJie Behavior Agree- 

 ment of the Animals of an Aquatic Community : 

 V. E. Shelpoed. 

 The Relation Between Bheotaxis and Resistance to 

 Potassium Cyanide in Isopoda: W. C. Allee. 

 The cyanide-resistance method which Professor 

 Child worked out as a measure for the metabolic 

 rate of planarians also holds for isopods. This is 

 demonstrated by the effects of changes in tempera- 

 ture and mechanical stimulation upon the survival 

 time in potassium cyanide; also by tests with young 

 and old isopods, and by comparing the survival 

 time and carbodioxide output in the same indi- 

 viduals. Average results from experiments on 

 452 isopods show that animals giving a highly 

 positive rheotactio response have the highest rate 

 of metabolism. Those giving a highly negative 

 reaction are next, while isopods giving a low posi- 

 tive and high negative or indefinite response have 

 a still lower metabolic rate. Isopods with a high 

 efficiency of movement in the current have a higher 

 rate of metabolism than those with low efficiency. 



These results support previous work on this sub- 

 ject. 



MISCELLANEOUS SUBJECTS 



The Reaction of the Honey Bee to Changes in Ex- 

 ternal Temperature: E. F. Phillips and Geoege 

 S. Demuth. 

 The Organs of Special Sense of Frorhyncus: Wil- 

 liam H. Kepnee and William H. Taliaferro. 

 The organs of special sense of this rhabdocele 

 are the eyes and the ciliated pits. The two eyes 

 lie beneath the epidermis, within the mesenchyme 

 in depressions at the dorsal surface of the ganglia. 

 The two ciliated pits open on the ventral side of 

 the body anterior to the anterior limits of the sur- 

 faces of the ganglia and midway between the 

 lateral surfaces of these cell masses and the mar- 

 gin of the body. 



One of the unique features of these four organs 

 is that they are formed of a definite number of 

 cells. There are only eighteen cells involved in 

 the formation of the four organs of special sense 

 of Frorhyncus. 



Each eye consists of two cells — an accessory or 

 pigmented cell and a retinular or visual cell. The 

 pigmented cell appears to be a modified mesenchy- 

 mal cell. Its mesial cytoplasm resembles that of 

 the typical mesenchymal cell. The lateral part of 

 its cytoplasm, however, has assumed a definite, 

 cup-like contour. This part of the cytoplasm, in 

 its fixed condition, presents concentric lamellee with 

 which the pigment of the cell is associated. The 

 mouth of this cup is directed laterally. 



The retinular cell appears to be a modified 

 nerve-element. Its nucleus has the characteristic 

 spheroidal contour of a nerve-cell. In the cyto- 

 plasm, in its fixed condition, there are three re- 

 gions. The lateral region is a finely granular 

 cone that lies closely applied to the dorsal surface 

 of the ganglion. The lateral end of this cone, we 

 infer, is continued as a nerve-fiber into the gang- 

 lion. The basal or mesial fourth of this cyto- 

 plasmic region accommodates the nucleus. The 

 middle cytoplasmic region of the retinular cell is 

 the densest region. It is a concavo-convex disc. 

 We are not prepared to say that this lens-shaped 

 region of cytoplasm acts as a lens for converging 

 the rays of light upon the pigment cell and rhab- 

 dome. We shall be content to look upon it as the 

 supporting structure of the mesial cytoplasmic re- 

 gion, which is the rhabdome of the visual cell. 

 The rhabdome is a low sugar loaf -shaped body that 

 fills the cup of the pigmented cell. 



The ciliated pits are invaginated regions of the 



