96 



Those separated at the two-celled stage lived to form plutei. 



Those separated at the four-celled stage formed regular blastulae in 

 most cases. 



Those separated at the eight-celled stage also formed regular blastulae. 



Experiment 4. — This is an experiment in artificial pai'thenogenesis in 

 arbacia. Plutei six days old were reared by Dr. H. .J. Hunter, of Kansas 

 University. He carried on the Avorlc longer and he has specially reported 

 on this, hence only this reference. 



These experiments are very interesting and may be of considerable 

 importance when we learn how to perfectly interpret them. 



The Eye of Pal^monetes Antrorum. 

 Edwin Manson Neher. 



Contributions from the Zoological Laboratory of the Indiana University, under the direc- 

 tion of C. H. Eigenmann. No. 47. 



A blind shrimp, FaUemonetes antrorum, evidently occurs in abund- 

 ance in the sul)terranean streams about San Marcos, Texas. It comes out 

 of the artesian well of the I'nited States Fish Commission at that place 

 in large numbers. The well is about one hundred and ninety feet deep 

 and has a yield of about one thousand gallons per minute. 



A brief description of Paheraonetes was published by Benedict, 1896. 



The material examined consists of yohng specimens, 5 to 5. .5 mm. long 

 from tip of rostrum to tip of telson and adult specimens measuring 15 

 mm. along the same line. Most of them were collected by Dr. C. H. 

 Eigenmann at the San :Marcos well in September, 1899. Others have since 

 been sent by Mr. .T. L. Leary. Superintendent of the United States Hatch- 

 ery at that place. 



The material at my disposal was preserved in 4 per cent, formalin. 

 The anterior end of the cephalo thorax was dehydrated and imbedded in 

 paraffin by the chloroform method. Sections were floated out on warm 

 water and fixed to the slide with glycerin-albumen and stained with 

 Mayer's haemalum, followed by eosine. Specimens of P. exilipes, which 

 were used for comparison, were treated with Perenyi's fluid for forty- 

 eight hours before imbedding and the sections were depigmented in 10 

 per cent, nitric acid for ten hours. The cuticle of the blind shrimp was 

 found to section readily without softening in Perenyi's fluid. 



