386 



SCIENCE 



[N. S., Vol. XL., No. 1028 



3. Clay, coarse and lumpy, witli some sand. 5 to 20 



4. "Natural sand-clay," feldspar, quartz, 



sand and clay 10 to 20 



5. Fragmental rock, angular, decayed, size 



2 to 4 in 10 to 20 



6. Fragmental rock, coarser and fresher 



than that in 5 5 to 15 



7. Granite, "bed rock," "country rock." 



This region serves as a type for Piedmont areas 

 in which granite is the underlying rock — about one 

 third of the Piedmont Belt. 



Zone No. 1 is the surface soil of the upland and 

 is used in agriculture and in road building. No. 2 

 provides clay suitable for brick and tile. As the 

 topography is mature and these zones have been 

 removed by erosion from much of the area, the 

 value of the land is low. The material of zone 4 

 makes good sand-clay roads. This is approxi- 

 mately horizontal and outcrops on the slopes where 

 valleys have been cut below its depth. Stream sand 

 is used in making mortar and in road construction. 



This mantle rock forms an excellent filter and 

 most wells in it are free from contamination. Ex- 

 cepting the mountain region, these are the most 

 healthful areas in the south. 



An Achlya of Syhrid Origm: W. C. Cokbr. 



An Achlya was described from C!hapel Hill, N. C, 

 with peculiarities that suggest a hybrid origin. 

 The tips of the hyphae often die and the growth Is 

 then extended as a side branch below the dead tip. 

 The spores show a strong tendency to poor organi- 

 zation, the protoplasm often segregating only im- 

 perfectly, and producing irregular masses of vari- 

 ous sizes. The same is true of the eggs, which are 

 of any size and almost never become perfectly or- 

 ganized, and die quickly. The plant seems most 

 like Achlya polyandra Hildeband, but differs from 

 it in the walls of the oogonia being pitted and in 

 the abnormal behavior of the eggs. 



It is suggested that the plant may be a hybrid 

 between A. DeBaryana Humphrey and A. apimi- 

 lata DeBary. 



Xhe Nurse SharJcs of Boca Gramde Cay, Florida: 



E. W. GUDGER. 



Boca Grande Cay is an island of coral sand and 

 mangroves lying about 20 miles west of Key West. 

 Situated on a shallow submariae platform, about 

 120° of its circumference is surrounded by sand 

 flats inhabited largely by sting rays. Another 

 120° of its circumference is bounded by a shallow, 

 gently sloping, rock bottom on which the water a 

 half mUe from shore wUl not be over a man's 



shoulders. On this rocky bottom, the nurse sharks, 

 Ginglymostoma cirratum, come out to bask in the 

 sun, to play, to breed, and possibly to feed. Here 

 they are found in large numbers. A dozen can be 

 seen at almost any time, and thirty-three have been 

 counted in the sweep of the eye. . 



These sharks in looks and habits much remind 

 one of well-fed pigs in a barnyard. They are much 

 broader in the pectoral region than ordinary sharks, 

 are sluggish in their movements, and are compara- 

 tively unafraid of man. They frequently lie in 

 water so shallow that their dorsals project above 

 the surface, and a number of times they allowed 

 the boat to drift down over them and strike their 

 fins before they would move. 



They lie with heads on each others pectorals or 

 tails, or one will have his snout elevated on 

 another 's flank, or they will lie heads and tails to- 

 gether or in a confused herd. Here again this 

 similarity of habits to barnyard pigs is very no- 

 ticeable. Further they often swim one after 

 another to the number of three or four in an aim- 

 less fashion, each one following the purposeless 

 turnings of its leader. 



They are perfectly harmless. Their mouths are 

 small and filled with small pointed teeth. They are 

 omnivorous in feeding like most sharks, but their 

 food seems chiefly to be crustacean, probably con- 

 sisting of the large spiny ' ' crawfish ' ' common on 

 the reef and on rocky bottom of any kind. 



Under the circumstances noted above, there is, 

 of course, no difficulty in* killing these sharks. 

 Ordinarily shark fishing is good sport, but killing 

 nurse sharks is no more exciting than sticking pigs 

 in a barnyard. Indeed the Key West fishermen 

 contemptuously speak of them as "Nurses," and 

 of the other sharks as ' ' sharks. ' ' 



Work on the habits and embryology of this 

 shark is being carried on under the auspices of the 

 Marine Laboratory of the Carnegie Institution of 

 Washington situated at Tortugas and will be con- 

 tinued this summer. 



Flowers and Seed Development of Specularia per- 

 foliata: H. B. Totten and J. A. McKay. 

 There are two kinds of flowers, conspicuous open 

 ones with normal corollas and small bud-like flow- 

 ers that never open. The last or eleistogamic flow- 

 ers were described carefully by von Mohl, as long 

 ago as 1863. 



It is the object of this paper to give the develop- 

 ment of the seeds iu the eleistogamic flowers. The 

 seeds are of the same size and appearance as those 

 borne in the open flowers. Four megaspores are 



